Waning immunity - recent finds -
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An ineffective argument
addition of references still in progress - 04/14/06
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=16585302&query_hl=1&itool=pubmed_docsum
Acellular pertussis vaccine booster combined with diphtheria
and tetanus toxoids for adolescents.
Pichichero ME,
Blatter MM,
Kennedy WA,
Hedrick J,
Descamps D,
Friedland LR.
University of Rochester Medical Center, Rochester, NY 14642, USA.
michael_pichichero@urmc.rochester.edu
BACKGROUND: The incidence of
pertussis
is increasing, especially in adolescents, attributed in part to waning of
immunity after childhood immunization. Recently licensed in the United
States for use in adolescents, acellular pertussis vaccines will provide an
immunogenic and safe option for booster immunization against pertussis. METHODS:
This prospective, randomized, observer-blinded, multicenter, comparative study
evaluated the safety and immunogenicity of a vaccine formulated with tetanus
toxoid, reduced diphtheria toxoid, and acellular pertussis antigens (Tdap)
compared with tetanus and diphtheria toxoids vaccine (Td) for booster
immunization in adolescents. There were 4114 healthy adolescents aged 10 to 18
years who completed childhood vaccination against diphtheria, tetanus, and
pertussis who were enrolled, randomized, and received study vaccine. RESULTS:
Local and general symptoms were comparable between the Tdap and Td groups. The
immune response of Tdap was comparable with Td vaccine for tetanus and
diphtheria seroprotection and booster responses. In addition, geometric mean
concentrations of antibody to pertussis antigens, pertussis toxoid, filamentous
hemagglutinin, and pertactin exceeded the antibody response elicited after
infant immunization with diphtheria and tetanus toxoids and acellular pertussis
antigens (DTaP) that had proven efficacy against pertussis. CONCLUSIONS: In
adolescents, the studied Tdap was safe and immunogenic and induced pertussis
antibodies that were higher than those associated with efficacy in infants.
PMID: 16585302 [PubMed - in process]
Immunogenicity and reactogenicity of a
reduced-antigen-content diphtheria-tetanus-acellular pertussis vaccine as a
single-dose booster in Singaporean adults.
Chan SH,
Tan PT,
Han HH,
Bock HL.
Department of Microbiology, Yong Loo Lin School of Medicine, National University
of Singapore, Block MD4, 5 Science Drive 2, Singapore 117597. hans.l.bock@gsk.com.
Introduction: Older children and adults,
susceptible to pertussis
because of waning immunity, may serve as a reservoir of infection,
leading to severe disease among young unvaccinated infants. Booster
diphtheria-tetanus-acellular pertussis (dTpa) vaccination in older age groups is
rare in Singapore, one reason being the increase in reactogenicity with each
successive dose. The aim of this study was to assess the immunogenicity, safety
and reactogenicity of a reduced antigen, combined dTpa vaccine as a single
booster dose in healthy adults aged 18 years or older. Methods: A total of 150
healthy adults, 18 to 60 years of age, received a single dose of GlaxoSmithKline
Biologicals' dTpa vaccine with reduced content for diphtheria and pertussis,
with measurement of pre- and post-vaccination antibody titres. Results: Prior to
vaccination, 71.6 percent and 92.6 percent of the subjects had anti-diphtheria
and anti-tetanus antibody levels greater than or equal to 0.1 IU/mL,
respectively. 46.7 percent, 98.5 percent and 44.4 percent of subjects were
seropositive for pertussis toxin (PT), filamentous haemagglutinin (FHA) and
pertactin (PRN) antibodies, respectively. One month after vaccination, there was
an increase in geometric mean titres from pre-vaccination to post-vaccination
blood samples for anti-diphtheria (greater than seven-fold), anti-tetanus
(greater than five-fold), anti-PT (greater than 11-fold), anti- FHA (greater
than 25-fold) and anti-PRN (greater than 31-fold) antibodies. Solicited grade
three local symptoms (pain, redness and swelling) were reported in 14.1 percent,
8.1 percent and 10.4 percent of subjects, respectively. No serious adverse
events were reported. Conclusion: In summary, the dTpa vaccine is immunogenic,
safe and well-tolerated in Singaporean adults.
PMID: 16572239 [PubMed - in process]
Relative efficacy of different immunization schedules for the
prevention of serogroup C meningococcal disease: A model-based evaluation.
De Wals P,
Trottier P,
Pepin J.
Faculty of Medicine, Laval University, Canada; Quebec National Institute of
Public Health, Canada.
Different immunization strategies have been implemented for the control of
serogroup C meningococcal disease (CMD) in Canada and in other developed
countries. Results from effectiveness
studies of conjugate vaccines in the UK and Spain indicate waning immunity over
time. To estimate the life-time protection conferred by different
immunization schedules, a simulation model was constructed based on the current
epidemiologic situation in Canada. Results showed that the efficacy of any
immunization schedule was highly influenced by the rate at which immunity waned
and that the benefit of a booster dose increased with increasing rates of waning
immunity. Schedules including several doses in early infancy provided little
additional benefit over programs starting with 1 dose at the age of 12 months.
One-dose programs provided low levels of protection, unless the vaccine was
administered at the age of 12 months, and a waning immunity rate of 1% per year
or less was assumed. The most effective schedule was 5 doses given at age 2
months, 4 months, 1 year, 12 years, and 18 years, but was only marginally better
than 2 doses provided at 12 months and 12 years of age. Existing routine
immunization schedules may not be optimal and should be designed to achieve the
highest level of protection using the lowest number of doses.
PMID: 16517032 [PubMed - in process]
Pertussis in infants, children, and adolescents: diagnosis,
treatment, and prevention.
Munoz FM.
Department of Pediatrics, Section of Infectious Diseases, and Molecular Virology
and Microbiology, Baylor College of Medicine, Houston, TX 77030, USA. florm@bcm.tmc.edu
Pertussis, or "whooping cough," caused by the gram-negative pleomorphic bacillus
Bordetella pertussis, is a highly contagious, potentially life-threatening
respiratory tract illness that has re-emerged worldwide as a cause of
substantial morbidity and mortality in infants, children, and adolescents,
despite high vaccination rates. Increased awareness and reporting, in addition
to the availability of better diagnostic tests, partially explain the recent
resurgence of pertussis. However, waning
immunity after childhood immunization has resulted in a growing pool of
susceptible adolescents and adults who are capable of transmitting
pertussis
to vulnerable unvaccinated or incompletely vaccinated infants. An
acellular pertussis vaccine booster for adolescents has been recommended in the
United States and other industrialized countries. Active immunization and early
diagnosis are crucial in the management of pertussis.
PMID: 16522501 [PubMed - in process]
Modelling the effect of a booster vaccination on disease
epidemiology.
Alexander ME,
Moghadas SM,
Rohani P,
Summers AR.
Institute for Biodiagnostics, National Research Council Canada, R3B 1Y6,
Winnipeg, Manitoba, Canada, Murray.Alexander@ncr-cnrc.gc.ca.
Despite the effectiveness of vaccines in dramatically decreasing the number of
new infectious cases and severity of illnesses, imperfect vaccines may not
completely prevent infection. This is
because the immunity afforded by these vaccines is not complete and may wane
with time, leading to resurgence and epidemic outbreaks notwithstanding high
levels of primary vaccination. To prevent an endemic spread of disease,
and achieve eradication, several countries have introduced booster vaccination
programs. The question of whether this strategy could eventually provide the
conditions for global eradication is addressed here by developing a
seasonally-forced mathematical model. The analysis of the model provides the
threshold condition for disease control in terms of four major parameters:
coverage of the primary vaccine; efficacy of the vaccine; waning rate; and the
rate of booster administration. The
results show that if the vaccine provides only temporary immunity, then the
infection typically cannot be eradicated by a single vaccination episode.
Furthermore, having a booster program does not necessarily guarantee the control
of a disease, though the level of
epidemicity
may be reduced. In addition, these findings strongly suggest that the
high coverage of primary vaccination remains crucial to the success of a booster
strategy. Simulations using estimated parameters for measles illustrate model
predictions.
PMID: 16283412 [PubMed - in process]
Adolescent and adult pertussis: disease burden and
prevention.
Edwards K,
Freeman DM.
Division of Infectious Diseases, CCC-5323 Medical Center North, Vanderbilt
University Medical Center, Nashville, Tennessee 37223, USA. Kathryn.Edwards@vanderbilt.edu
PURPOSE OF REVIEW: According to
surveillance data provided by the Centers for Disease Control and Prevention,
the rates of pertussis
disease in adolescents and adults have been increasing. This is likely due to
increased recognition and waning vaccine-induced immunity. RECENT
FINDINGS: The presentation of pertussis in adolescents and adults is generally a
persistent cough, but more serious complications have been reported. In
addition, adolescents and adults often serve as sources of pertussis infection
in infants and young children. SUMMARY: Acellular pertussis vaccines combined
with diphtheria and tetanus toxoids have proven to be well tolerated,
immunogenic and effective in reducing pertussis disease in adolescents and
adults. These vaccines are currently being recommended to replace the booster
diphtheria and tetanus toxoid vaccines in adolescents. Recommendations for the
use of these vaccines in adults are still being formulated.
PMID: 16470167 [PubMed - in process]
Are vaccination programs and isolate polymorphism linked to
pertussis re-emergence?
Godfroid F,
Denoel P,
Poolman J.
DAP Bacterial Vaccine Preclinical Immunology, Research & Development,
GlaxoSmithKline Biologicals, Rue de l'Institut 89, 1330 Rixensart, Belgium.
fabrice.godfroid@gskbio.com
Whooping cough remains an endemic disease, and the re-emergence of pertussis in
older children and adolescents has been reported in several countries, despite
high vaccine coverage. Polymorphism of Bordetella pertussis has been observed
over time, and some characteristics of pertussis isolates have gradually
diverged from the vaccine strains. The present review summarizes the current
knowledge on B. pertussis variability in countries with different vaccination
programs and discusses its potential impact on the recently observed increased
incidence of whooping cough. No direct association between B. pertussis isolate
variability and vaccination programs has been observed to date, except for
shifts from fimbriae Fim2 to Fim3. More
likely explanations for the re-emergence of
pertussis
include the change in the epidemiology and transmission patterns of
pertussis
in highly vaccinated populations, and a shift of disease from young children to
adolescents and adults due to waning protective immunity.
PMID: 16221076 [PubMed - in process]
Pertussis: old foe, persistent problem.
Sabella C.
Division of Pediatrics, Section of Pediatric Infectious Diseases, The Children's
Hospital, The Cleveland Clinic Foundation, OH 44195, USA. sabellc@ccf.org
Although a safe and effective vaccine is available, pertussis continues to be an
important cause of morbidity and mortality.
Immunity acquired from natural infection
or vaccination wanes within 5 years, making older children, adolescents, and
adults important reservoirs of infection. Many neonates and infants
contract pertussis from older people with mild symptoms and are at risk for
developing severe, life-threatening illness. Immunization programs are being
considered for adolescents and for adults who live with or care for infants.
Publication Types:
PMID: 16044656 [PubMed - in process]
Environmentally and occupationally acquired diseases in
adolescents and adulthood: control of diphtheria, tetanus, pertussis, and
poliomyelitis through regular booster vaccinations--a European perspective.
Hofmann F.
Lehrstuhl fur Arbeitsphysiologie, Arbeitsmedizin und Infektionsschutz, Bergische
Universitat Wuppertal, Gaussstrasse 20, 42097 Wuppertal, Germany.
Despite the success of childhood
vaccination in industrialized countries, diphtheria, tetanus,
pertussis
(whooping cough), and poliomyelitis (polio) still affect adults and adolescents
whose immunity has waned. The resurgence in the 1990s of diphtheria in
the area of the former Soviet Union and its subsequent control with immunization
campaigns, demonstrates the value of continued adult vaccination. Tetanus cannot
be eradicated from the soil reservoir, necessitating routine primary vaccination
and regular booster doses to maintain protective immunity. Although Europe has
been certified endogenous polio-free since June 2002, polio imported from
endemic areas continues to pose a serious threat for vulnerable populations.
Booster polio vaccination is required in adolescence and adulthood. Pertussis
among adults and adolescents is underestimated, representing a considerable
health burden. The consequences can be more serious as this pool of susceptible
adolescents and adults is a major source of pertussis transmission to newborns
not yet protected by vaccination. The now available acellular pertussis-based
combination vaccine covering diphtheria, tetanus, polio, and pertussis, suitable
for adults and adolescents, provides the ideal tool for implementing booster
immunization programs. Strong recommendations for adolescent and adult boosters
are needed to overcome the continued threat of these diseases.
PMID: 16422349 [PubMed - indexed for MEDLINE]
Prevention of pertussis among adolescents: recommendations
for use of tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis (Tdap)
vaccine.
America Academy of Pediatrics Commitee on Infectious Diseases.
The purpose of this statement is to provide the rationale and recommendations
for adolescent use of tetanus toxoid, reduced diphtheria toxoid, and acellular
pertussis (Tdap) vaccines. Despite universal immunization of children with
multiple doses of pediatric diphtheria and tetanus toxoids and acellular
pertussis (DTaP) vaccine, pertussis remains endemic with a steady increase in
the number of reported cases. Two peaks
in the incidence of pertussis
occur in pediatric patients: infants younger than 6 months of age who are
inadequately protected by the current immunization schedule and adolescents 11
through 18 years of age whose vaccine-induced immunity has waned.
Significant medical and public health resources are being consumed in
postexposure management of adolescent cases, contacts, and outbreaks with little
beneficial effect on individuals or the epidemiology of disease. Two Tdap
products were licensed in 2005 for use in people 10 through 18 years of age (Boostrix)
and 11 through 64 years of age (Adacel). The American Academy of Pediatrics
recommends the following: 1. Adolescents 11 to 18 years of age should receive a
single dose of Tdap instead of tetanus and diphtheria toxoids (Td) vaccine for
booster immunization. The preferred age for Tdap immunization is 11 to 12 years.
2. Adolescents 11 to 18 years of age who have received Td but not Tdap are
encouraged to receive a single dose of Tdap. An interval of at least 5 years
between Td and Tdap is suggested to reduce the risk of local and systemic
reactions; however, intervals of less than 5 years can be used, particularly in
settings of increased risk of acquiring pertussis, having complicated disease,
or transmitting infection to vulnerable contacts. Data support acceptable safety
with an interval as short as approximately 2 years. 3. Tdap and tetravalent
meningococcal conjugate vaccine (MCV4 [Menactra]) should be administered during
the same visit if both vaccines are indicated. If this is not feasible, MCV4 and
Tdap can be administered using either sequence. When not administered
simultaneously, the American Academy of Pediatrics suggests a minimum interval
of 1 month between vaccines. The rationale for this strategy is to provide
direct protection of immunized adolescents. With implementation of vaccine
recommendations, indirect benefitalso is likely to extend to unimmunized peers
and other age groups. The strategy of universal Tdap immunization at 11 to 12
years of age is cost-effective.
Publication Types:
PMID: 16382131 [PubMed - indexed for MEDLINE]
J Adolesc Health. 2005 Dec;37(6):517. Related Articles, Links
Immunogenicity and reactogenicity of a
reduced-antigen-content diphtheria-tetanus-acellular pertussis vaccine in
healthy Taiwanese children and adolescents.
Huang LM,
Chang LY,
Tang H,
Bock HL,
Lu CY,
Huang FY,
Lin TY,
Lee CY.
Department of Pediatrics, National Taiwan University Hospital, Taipei, Taiwan.
PURPOSE: Disease caused by
Bordetella
pertussis
is increasingly being identified among older children and adults in immunized
populations, indicating a waning of the vaccine-induced immunity. These
findings suggest the need for booster immunization of older children and adults.
Modern acellular reduced-antigen-content vaccines have been developed, which can
be given as a booster in individuals more than 4 years of age. This study was to
assess the immunogenicity and reactogenicity of Boostrix, GlaxoSmithKline
Biologicals' reduced-antigen-content diphtheria-tetanus acellular pertussis (dTpa)
vaccine, when administered as a booster in healthy subjects previously primed
with DTP vaccine. METHODS: Healthy Taiwanese children and adolescents aged 6-8
years and 15-20 years, previously primed with DTP vaccine, were enrolled. All
received one dose of Boostrix. Two blood samples were taken from each of them,
one before vaccination and one at 1 month after vaccination. Serum antibodies to
diphtheria and tetanus toxoids and immunoglobulin G (IgG) antibodies against the
pertussis components PT, FHA and PRN were measured by enzyme-linked
immunosorbent assay (ELISA) technique. Adverse reactions following vaccination
were recorded. RESULTS: A total of 180 subjects were recruited. The vaccine
response rates to the pertussis antigens ranged between 89.0-100%. There were no
serious adverse events reported during the study period. CONCLUSIONS: The
results of this study suggest that Boostrix may be safely and effectively
administered as a booster dose to children previously primed with DTP vaccine.
Publication Types:
PMID: 16310132 [PubMed - indexed for MEDLINE]
Pertussis: increasing disease as a consequence of reducing
transmission.
Aguas R,
Goncalves G,
Gomes MG.
Instituto Gulbenkian de Ciencia, Oeiras, Portugal.
Since the 1980s, the occurrence of
pertussis
cases in developed countries has increased and shifted towards older age groups.
This resurgence follows 30 years of intense mass vaccination, and has been
attributed primarily to three factors: (1) more effective diagnosis of the
disease, (2) waning of vaccine-induced immunity, and (3) loss of vaccine
efficacy due to the emergence of new
Bordetella
pertussis
strains. Here we develop and analyse a mathematical model to assess the
plausibility of these hypotheses. We
consider that exposure to B
pertussis through natural
infection or vaccination induces an immune response that prevents severe disease
but does not fully prevent mild infections. We also assume that these protective
effects are temporary due to waning of immunity. These assumptions, describing
the mode of action of adaptive immunity, are combined with a standard
transmission model. Two distinct epidemiological scenarios are detected: under
low transmission, most infections lead to severe disease; under high
transmission, mild infections are frequent, boosting clinical immunity and
maintaining low levels of severe disease. The two behaviours are
separated by a reinfection threshold in transmission. As a result, the highest
incidence of severe disease is expected to occur at intermediate transmission
intensities--near the reinfection threshold--suggesting that pertussis
resurgence may be induced by a reduction in transmission, independently of
vaccination. The model is extended to interpret the outcomes of current control
measures and explore scenarios for future interventions.
PMID: 16439331 [PubMed - indexed for MEDLINE]
The reemergence of pertussis in immunized populations: a case
study.
Dominguez D.
The University of Texas at El Paso, College of Health Sciences, 79902, USA.
delfina@utep.edu
OBJECTIVE: To present a case of classical pertussis occurring in previously
vaccinated male siblings, 11 and 13 years of age, living in El Paso TX; also to
present an overview and update of the changing epidemiology of pertussis
including pathophysiology, diagnosis, and treatment. DESIGN: Nasopharyngeal
swabs and blood samples were collected from two male siblings, 11 and 13 years
of age, presenting with cold-like symptoms and persistent cough during the
second week of infection. Nasopharyngeal swabs were plated onto Bordet-Gengou
agar plates and incubated for 48 hours. Blood samples were analyzed for the
presence of antibodies (IgM and IgA) against Bordetella pertussis antigens using
indirect enzyme linked immunosorbent assay (ELISA). SETTING: Cultures and
serological analysis was conducted at the University of Texas at El Paso,
Clinical Laboratory Science Program Research facility. RESULTS: Bacterial
cultures of both children were positive for Bordetella pertussis and the sera
revealed positive IgM and IgA antibodies (> 11 PANBIO UNITS) against a mixture
of antigens including: pertussis toxin, filamentous hemagglutinin, pertactin,
and fimbriae. CONCLUSIONS: Pertussis
immunity wanes overtime, leaving most adolescents and adults susceptible to
infection. Physicians must be prepared to diagnose and treat pertussis in
any age group regardless of vaccination status.
Publication Types:
PMID: 16315741 [PubMed - indexed for MEDLINE]
Emerging diseases: measles.
Ota MO,
Moss WJ,
Griffin DE.
W. Harry Feinstone Department of Molecular Microbiology and Immunology,
Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland
21205, USA. mota@jhsph.edu
High vaccination coverage rates and the
administration of a second dose of measles vaccine have resulted in a
significant decline in the incidence of measles and
neurologic
diseases due to measles in many countries. However, intermittent outbreaks of
measles still occur even in countries with excellent vaccination coverage,
suggesting the existence of high rates of measles virus introduction from
endemic regions and/or waning of vaccine-induced immunity. Strategies to
sustain high levels of global immunity to measles virus by increasing vaccine
coverage with routine and supplementary vaccination campaigns must be supported.
Publication Types:
PMID: 16287686 [PubMed - indexed for MEDLINE]
Pertussis vaccination for adolescents and adults.
Franco E,
Giambi C,
Ialacci R,
Maurici M.
University Tor Vergata, Department of Public Health, Via Montpellier, 1 00133
Rome, Italy. franco@med.uniroma2.it
Following the introduction of vaccines, the incidence of pertussis declined;
however, since 1990, a progressive increase was noted, even in highly immunised
populations. Periodic
pertussis
outbreaks are due to suboptimal efficacy of the vaccine and waning immunity with
increasing age. A significant proportion of adolescents and adults with a
prolonged cough present Bordetella pertussis, and infection is often transmitted
to infants too young to be vaccinated. A high vaccination coverage in the whole
population would be necessary to interrupt the circulation of B. pertussis, but
immunisation programmes for adolescents and adults have been introduced recently
and are accepted with difficulty. The lack of cost-benefit analysis and
consistent epidemiological data makes it difficult to assess the role of
pertussis elimination among public health priorities. At present, programmes
targeted at risk groups for close contacts with infants are the most convenient
for adult population, as more epidemiological and economic evidence is needed
before a universal strategy can be discussed.
Publication Types:
PMID: 15461578 [PubMed - indexed for MEDLINE]
Health and economic consequences of an outbreak of pertussis
among healthcare workers in a hospital in France.
Ward A,
Caro J,
Bassinet L,
Housset B,
O'Brien JA,
Guiso N.
Caro Research Institute, Concord, Massachusetts, USA. alexward@caroresearch.com
BACKGROUND: Bordetella
pertussis
is highly contagious, and because immunity wanes after vaccination, it continues
to be a cause of cough among adults. OBJECTIVE: To describe the
healthcare services used and productivity losses accrued by healthcare workers (HCWs)
missing work due to pertussis. METHODS: After 3 pertussis cases were confirmed
among HCWs, all hospital employees and patients with a cough were screened
between November 2000 and March 2001. Each potential case underwent diagnostic
tests and received antibiotics (spiramycin or azithromycin) when appropriate.
Symptomatic employees were not allowed to return to work until they received an
antibiotic for at least 5 days. Services used (physician visits and calls,
antibiotics, diagnostic tests, hospitalization, and treatment provided to their
contacts) were combined with cost estimates (in 2002 euros) for these services
in France. RESULTS: Ninety-one potential cases were identified (77 HCWs, 12
patients, and 2 family members). Of them, 89% received antibiotics and 22% had
at least one contact who was also treated. Approximately half (55%) of the HCWs
who were cases missed 5 days of work. Four patients were admitted to the
hospital as a result of the infection. The average medical cost was 297 euros
per potential case: diagnostic tests accounted for 32% and hospitalization for
31%. Total cost (medical and productivity) was 46,661 euros for 91 cases, 42%
from productivity losses. An investigation to identify these potential cases
also accrued additional costs. CONCLUSION: Serious adverse health and economic
consequences arose from transmission of pertussis among HCWs, their families,
and patients.
PMID: 15796282 [PubMed - indexed for MEDLINE]
Prevention of hepatitis B in nonresponders to initial
hepatitis B virus vaccination.
Sjogren MH.
Department of Clinical Investigation, Walter Reed Army Medical Center,
Washington, District of Columbia 20307, USA.
Although vaccination against hepatitis B virus (HBV) is highly successful, 5% to
10% of individuals do not experience a response with an adequate antibody level
to hepatitis B surface antigen (anti-HBs). Contributing causes for nonresponse
to the vaccine are genetic predisposition, immunosuppression, and certain
chronic illnesses. The distinction
between true nonresponse
(after adequate immunization) and waning anti-HBs
levels is important. The latter is not uncommon in populations in areas of the
world with low endemicity
for HBV
infection. Data from subjects with waning anti-HBs levels show that
immunologic memory may still protect these individuals against acute HBV
infection or may prevent chronic infection with HBV for < or =10 years after
immunization. Recent reports from Asia and Alaska describe cases of chronic HBV
infection 15 years after immunization in subjects who have very low levels of
anti-HBs. Thus,
nonresponders
or those with waning immunity who may be at risk of
HBV
infection in subsequent years may require a booster dose. Clinical
algorithms to reimmunize nonresponders have been described and are discussed in
this article. Experimental hepatitis B vaccines have shown some promise in
nonresponders but are not commercially available in the United States.
Publication Types:
PMID: 16271539 [PubMed - indexed for MEDLINE]
Diagnosis and management of pertussis.
Tozzi AE,
Celentano LP,
Ciofi degli Atti ML,
Salmaso S.
Epidemiology Unit, Bambino Gesu Hospital, Rome, Italy. alberto.tozzi@opbg.net
Pertussis
is increasing in frequency among children too young to be vaccinated and among
adolescents and adults. This increase is due mainly to waning immunity among
vaccinated individuals, who become susceptible during adolescence and adulthood
and maintain the circulation of
Bordetella
pertussis.
Infants are at highest risk of severe illness requiring hospital admission,
complications and death. The clinical presentation in adolescents, adults and
vaccinated individuals may be atypical, with paroxysmal cough of short duration
or simply a persistent cough. Culture and polymerase chain reaction may be used
to identify B. pertussis infection, but their sensitivity is high only in the
early phase of the disease. Serologic tests are not standardized for the
diagnosis of pertussis, and their clinical application is limited. Erythromycin
is still considered in some countries to be the "gold standard" for therapy and
prophylaxis; however, azithromycin and clarithromycin seem equally efficacious
and are associated with fewer side effects.
Publication Types:
PMID: 15710944 [PubMed - indexed for MEDLINE]
Pertussis sources of infection and routes of transmission in
the vaccination era.
Schellekens J,
von Konig CH,
Gardner P.
Diagnostic Laboratory for Infectious Diseases and Perinatal Screening, RIVM,
Bilthoven, the Netherlands. j.schellekens@infectielab.nl
Vaccination against
pertussis
has resulted in reduction of the infection pressure of
Bordetella
pertussis
(partial herd immunity), but the circulation of B.
pertussis
has persisted as a consequence of waning of vaccine-induced and naturally
acquired immunity. An increase in the reported incidence of B. pertussis
infection in older children, adolescents and young adults has been noted,
resulting in a perceived resurgence of the disease in these age groups.
Regardless of whether this resurgence is real or not, older groups are
increasingly recognized as playing an important role in transmitting B.
pertussis infection to incompletely immunized infants, in whom pertussis disease
continues to cause severe and fatal illness, albeit at much lower levels than in
the prevaccine era. Several studies have suggested that mothers, in particular,
are a significant source of infection for infants. Adolescents, grandparents and
health care workers can also play a role. By contrast, most adolescents acquire
the infection from schoolmates and friends, whereas for adults the main sources
are children and work colleagues. Furthermore teachers, child care workers and
health care workers could be at increased risk of being exposed to, and
transmitting, B. pertussis infection. Current immunization strategies
inadequately control the circulation of B. pertussis, in part because of
suboptimal adherence to current pediatric immunization guidelines. In addition
to efforts to improve pertussis immunization rates in children, the expansion of
pertussis immunization to target specific groups should be considered. Besides
reducing morbidity in the targeted groups, these strategies could decrease the
residual burden of pertussis morbidity and mortality in infants.
Publication Types:
PMID: 15876919 [PubMed - indexed for MEDLINE]
[Increase in the number of invasive Haemophilus influenzae
type b infections]
[Article in Dutch]
Spanjaard L,
van den Hof S,
de Melker HE,
Vermeer-de Bondt PE,
van der Ende A,
Rijkers GT.
Academisch Medisch Centrum/Universiteit van Amsterdam, Nederlands
Referentielaboratorium voor Bacteriele Meningitis, L-1-Z, Postbus 22.660, 1100
DD Amsterdam. l.spanjaard@amc.uva.nl
OBJECTIVE: To describe the increase of invasive Haemophilus influenzae type b (Hib)
infections in The Netherlands before and after the introduction of Hib
vaccination in 1993, and to hypothesise about possible explanations. DESIGN:
Descriptive. METHOD: Data on the prevalence of invasive Hib infections, such as
meningitis and epiglottitis, during 1990-2004 were obtained from The Netherlands
Reference Laboratory for Bacterial Meningitis, which collects Hib isolates from
spinal fluid and blood from across the country. RESULTS: The incidence of
invasive Hib infections decreased substantially for a few years after 1993. The
total number of isolates was at a minimum in 1999 (n = 12) and increased to 49
in 2004. The annual number of patients with vaccine failure was 5 or less during
1995-2001, but was between 10 and 15 from 2002 onwards. A definite explanation
for the increase in the incidence of invasive Hib infections cannot be given.
Improbable causes are a surveillance artefact, an impaired response to the
vaccine due to vaccination-scheme changes or interaction with other vaccines, or
selection of Hib variants that are less sensitive to the vaccine-induced
immunity. It most likely involves
secondary vaccine failure: Hib
carriership
is decreased by mass vaccination, whereupon natural boosting occurs less
frequently later in life. Subsequently, immunity decreases and susceptibility to
invasive infection increases. Careful surveillance of invasive Hib
infections in The Netherlands remains important.
PMID: 16375019 [PubMed - indexed for MEDLINE]
Measles in Minsk, Belarus, 2001-2003: clinical, virological
and serological parameters.
Atrasheuskaya AV,
Blatun EM,
Neverov AA,
Kameneva SN,
Maksimov NL,
Karpov IA,
Ignatyev GM.
Laboratory of Immunology Safety, Institute of Molecular Biology, State Research
Center of Virology and Biotechnology Vector, Koltsovo, Novosibirsk Region
630559, Russia. ignat@vector.nsc.ru
BACKGROUND: A number of cases of measles
have been reported in the Republic of Belarus despite vaccine coverage of 98%.
The absence of information on measles virus genotypes circulating in the
Republic of Belarus has made it difficult to asses the situation. OBJECTIVES:
The purpose of this study was to isolate and sequence measles virus strains from
clinical cases in Minsk, Belarus, and to estimate the role of vaccine failure in
those cases. STUDY DESIGN: Between 2001 and 2003 years, 14 measles cases
admitted to the Hospital of Infectious Diseases of Minsk were enrolled in our
study. Clinical, routine laboratory, as well as serological and virological
examinations were carried out. Detection of measles antibodies and IgG avidity
testing was performed using commercial test kits. All measles cases were
confirmed by RT-PCR and phylogenetically characterized. RESULTS: Only 42.9% of
the cases met the WHO laboratory criteria for measles, however, all cases were
confirmed by RT-PCR. Most of the measles cases were attributed to secondary
vaccine failure (SVF). Phylogenetic analysis revealed the presence of genotype A
virus strains in 2001 and 2002 with D6 and D7 genotypes in 2003. CONCLUSIONS:
For the first time, MVs were genetically characterized in Belarus.
Our results suggest that in a highly vaccinated population, most of measles
cases represent vaccine failures and are vaccine-modified. Our results also
indicate that confirmation of a clinical diagnosis of vaccine-modified measles
requires a combination of serological and
virological
tests.
PMID: 16214679 [PubMed - indexed for MEDLINE]
Duration of immunity against pertussis after natural
infection or vaccination.
Wendelboe AM,
Van Rie A,
Salmaso S,
Englund JA.
Department of Epidemiology, University of North Carolina-Chapel Hill, Chapel
Hill, NC 27599, USA. awendelboe@unc.edu
Despite decades of high vaccination coverage, pertussis has remained endemic and
reemerged as a public health problem in many countries in the past 2 decades.
Waning of vaccine-induced immunity has
been cited as one of the reasons for the observed epidemiologic trend. A review
of the published data on duration of immunity reveals estimates that
infection-acquired immunity against
pertussis
disease wanes after 4-20 years and protective immunity after vaccination wanes
after 4-12 years. Further research into the rate of waning of
vaccine-acquired immunity will help determine the optimal timing and frequency
of booster immunizations and their role in pertussis control.
Publication Types:
PMID: 15876927 [PubMed - indexed for MEDLINE]
Potential strategies to reduce the burden of pertussis.
Forsyth K,
Tan T,
von Konig CH,
Caro JJ,
Plotkin S.
Flinders University, Adelaide, Australia. Kevin.Forsyth@flinders.edu.au
Pertussis
continues to be a significant cause of morbidity and mortality among
nonimmunized
young infants. Although the inception of childhood
pertussis
immunization programs has significantly reduced the occurrence of the disease in
children, waning vaccine-induced immunity permits the disease to affect
adolescents and adults, who in turn transmit the disease to
unimmunized
or incompletely immunized infants. The Global Pertussis Initiative
brought together experts from 17 countries around the world to evaluate
strategies to improve disease control. Seven strategies were considered: (1)
universal adult immunization; (2) selective immunization of mothers and close
family contacts of newborns; (3) selective immunization of health care workers;
(4) selective immunization of child care workers; (5) universal immunization of
adolescents; (6) preschool booster at 4-6 years of age; and (7) reinforcement
and/or improvement of current infant and toddler immunization strategies.
Because immunization programs vary widely from country to country, no single
strategy is likely to be appropriate for all. Moreover it would be helpful to
have additional data to support the strategies and provide a better
understanding of the disease so that new approaches can be monitored
effectively. However, certain steps can be taken now to reduce the incidence of
pertussis.
Publication Types:
PMID: 15876930 [PubMed - indexed for MEDLINE]
Pertussis immunization in the global pertussis initiative
North American region: recommended strategies and implementation considerations.
Tan T,
Halperin S,
Cherry JD,
Edwards K,
Englund JA,
Glezen P,
Greenberg D,
Rothstein E,
Skowronski D.
Division of Infectious Diseases, Northwestern University's Feinberg School of
Medicine, The Children's Memorial Hospital, Chicago, IL 60614, USA. titan@childrensmemorial.org
In North America, children currently
receive 5 doses of a combined diphtheria-tetanus-acellular
pertussis
vaccine between the ages of 2 months and 6 years. Although this schedule has
reduced the incidence of childhood
pertussis,
it has not led to the development of herd immunity in the total population,
largely because pertussis
immunity wanes with time. The time course over which immunity wanes is
uncertain; however, high
pertussis antibody titers in
adolescents and adults indicate unrecognized infection in these groups.
There is evidence that this group serves as a source of infection for young
infants who are not fully immunized. Therefore, of the potential strategies
reviewed by the North American Global Pertussis Initiative group, universal
adolescent immunization would in theory reduce the risk of pertussis in this age
group and may reduce transmission to young infants. However, because immunity
probably wanes at the same rate in adolescents and children, the burden of
disease will likely shift to older age groups, including young adults (parents
of vulnerable infants). Therefore the ideal would be immunization of adolescents
and adults, particularly those who are in contact with young infants. Adolescent
immunization is already recommended in Austria, France, Germany and Canada, and
participants in the Global Pertussis Initiative recommend that this strategy be
implemented across North America with a view to eventually extending
immunization to include adults. The final decision to implement such a strategy
will depend on pertussis surveillance studies and analysis of the effectiveness
and tolerability of adolescent and adult pertussis immunization as well as
program considerations related to feasibility and economics.
Publication Types:
PMID: 15876933 [PubMed - indexed for MEDLINE]
Pertussis immunization in the global pertussis initiative
international region: recommended strategies and implementation considerations.
Forsyth K,
Nagai M,
Lepetic A,
Trindade E.
Department of Paediatrics, Flinders Medical Centre, Flinders University,
Adelaide, Australia. Kevin.Forsyth@flinders.edu.au
Despite widespread immunization programs in most countries, pertussis disease
continues to be a threat to public health. In particular, there has been a
resurgence of pertussis disease in older children, adolescents and adults,
creating a reservoir of infection, which poses a significant threat to infants
who are either unimmunized or incompletely immunized. Global Pertussis
Initiative participants from Argentina, Australia, Brazil and Japan considered
the relative merits of several strategies to reduce the burden of pertussis
disease and suggested strategies that might be implemented in these countries.
Infants in these countries receive an initial course of 3 doses of vaccine in
the first year of life followed by a fourth dose in the second year. Only
children in Japan are not given a preschool booster (age 3-5 years).
Of the strategies considered, the
addition of a preschool booster is therefore a priority in Japan to overcome the
problem of waning vaccine-induced immunity to
pertussis
in school children. Waning immunity also affects adolescents; Australia
introduced an adolescent booster in 2003, and the addition of a booster in this
age group was suggested for Argentina and Japan. Immunization of new mothers and
other close contacts of young infants, such as child care and health care
workers, might be appropriate in Australia in the future. Argentina also
suggested a future possibility of immunizing health care and child care workers.
Obstacles to new immunization strategies include poor access to standardized
laboratory diagnostic techniques, inadequate resources to fund new immunization
programs, low awareness of pertussis disease in adults and adolescents and
inadequate surveillance techniques to assess the full extent of the problems
caused by pertussis or the impact new vaccination strategies might have.
Publication Types:
PMID: 15876935 [PubMed - indexed for MEDLINE]
Erratum in:
- Pediatr Infect Dis J. 2005 Nov;24(11):983.
Pertussis in adolescents: increasing incidence brings
attention to the need for booster immunization of adolescents.
Greenberg DP.
Scientific and Medical Affairs, sanofi pasteur, Swiftwater, PA 18370, USA.
david.greenberg@sanofipasteur.com
As a result of waning immunity and
improved awareness, the reported incidence of
pertussis
is increasing among adolescents in the United States. Symptoms of
pertussis are often mild and difficult to diagnose in adolescents, but these
individuals can transmit the infection to schoolmates and family members,
including high risk infants. Improvements in diagnosis and prevention of
pertussis in adolescents are needed.
Publication Types:
PMID: 16094229 [PubMed - indexed for MEDLINE]
[Vaccinations in adults--who? when? why?]
[Article in German]
Hofmann F.
Fachgebiet Arbeitsphysiologie, Arbeitsmedizin und Infektionsschutz, Bergische
Universitat Wuppertal. fhofmann@uni-wuppertal.de
Despite the success of childhood
vaccinations in Europe, many infectious diseases pose a threat to adults,
particularly because immunity induced by vaccination is not life long in some
cases. This paper presents the rationale for adult boosters for
diphtheria, hepatitis B, pertussis, poliomyelitis and tetanus. Moreover
indication for adult-vaccinations against measles, mumps, German measles and
varicella is discussed, as a significant part of the population in Germany is
susceptible or without known immunity/vaccination history. Finally, immunisation
of the elderly against infections with influenza-virus and S. pneumoniae will be
described.
PMID: 15655680 [PubMed - indexed for MEDLINE]
Vaccination against hepatitis B virus: are Thai medical
students sufficiently protected?