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ACIP Meeting Personal, Unofficial Summary of R.K. Zimmerman, M.D. June 19-20, 2002 Atlanta,GA Smallpox Charge: 1. With no known cases, should there be expanded recommendations? 2. Are there other specific occupational groups that should be vaccinated? 3. Should there be any change in the recommendation that the ring strategy be the primary response strategy?
Question 1 - Pre-exposure vaccination for general public Option 1 - not recommend for general public - no change Option 2 - not recommended but permissive Option 3 - no statement, permissive Option 4 - recommend for those who want it Question 2 - Specific occupational groups Option 1 - not recommended except for specific laboratory or medical personnel working with non-attenuated orthopox viruses - hundreds would be vaccinated Option 2 - recommended for smallpox response teams and designated facilities - thousands would be vaccinated Option 3 - Essential medical personnel: hundreds of thousands if ER physicians, millions if more expansive Question 3 - Smallpox control Option 1 - ring strategy Option 2 - ring strategy and first responders/essential medical personnel Option 3 - ring strategy plus affected community and neighboring vaccination Option 4 - ring strategy plus mass vaccination of the United States Spread is by large droplets that fall to the ground typically within 6 feet. Transmission is primarily by direct, face-to-face contact within 6-7 feet. Airborne transmission is rare. Fomites are rare. An N-95 mask should interrupt transmission. Cough is unusual but increases transmission by the airborne route. There is no carrier state. Although the virus is in crusts, it is protein bound and less contagious. Factors influencing spread include temperature, humidity, duration of contact, intensity of contact, contagious period, population density, and coughing/sneezing. The average number of secondary cases (R0) is 5-7, in contrast to measles where it is 12-18. The average secondary attack rates in unvaccinated households was 58%. In European transmissions, 55% of cases were hospital acquired, 20% of family and intimate contacts, and 8% were work-related (laundry of sheets). Pre-exposure vaccination No controlled trials. Secondary attack rate studies in family contacts were based on scar history, not vaccine take, and did not assess vaccine potency. Vaccine efficacy was 91% to 97%. The duration of efficacy in JID 1990;161:446-8 in Israel from Lister strain persisted 30 years when 3 doses of vaccine given. Another study JID 1972;125:161-9 showed modest decline in protection with time since vaccination; fatality rate about 10% in those vaccinated 20 years previously compared to 50% in unvaccinated. The determinants of long-term immunity is unknown. There is evidence for persistence of both antibody and cell-mediated immunity. Adverse reactions include fever 10%, myalgias 50%, lymphadenopathy in 39%, and injection site pain 32%. Induration occurs in 16%. Frey NEJM 2002;346:1265-80. Pruritis occurs in most vaccinees. Did 121 smallpox outbreak investigations in Pakistan. In Pakistan, >25% unvaccinated. Importations occurred about every 10 years in a village. In 27% of cases, no transmission. In another 37% of outbreaks, only one generation. In 49 importations to Europe, 27% no transmission. If terrorist introduction, small number of cases. Suicide dissemination difficult. Airborne spread inefficient except in closed space such as airplane. Availability of designated protected personnel is key. Avoid hospitalization. Pre-exposure vaccination to field personnel and selected providers. Not vaccinate ER, firefighters, nor physicians. Believes that economic growth contributed to elimination. Recommendations: option 1 to Q1,option 2 to Q2, option 1 to Q3. Disease moves slowly; transmission not during prodrome. Spread is slow and virtually all cases gave history of prolonged face-to-face contact. Failure of mass vaccination was evident. In the ring strategy, search for cases, quarantine, vaccinated contacts and the contacts of contacts. Surveillance and containment was more effective than mass vaccination in Bull WHO 1975;52:209-222. In AJE 1971;91:316-26, attack rates 27% in constant exposure and 6% of daily exposure. Case identification would be easier today due to media. Rigorous isolation would be easier today due to N95 masks and individual housing. Identification of contacts may be easier with media. Vaccination of contacts easier as public demand it in contrast to former distrust of government. Surveillance of contacts for fever was labor intensive and limited thermometers; easier with phone, email, visiting nurses, and available thermometers. Identification of second ring may be more difficult now. Communication with second ring members was difficult and would be easier now. Relative of second ring members was difficult when multiple villages involved and would be unknown here. Overall, easier today with better communications and better education. Intense inflammatory response around vaccination site. Rash complications include erythema multiforme, bacterial superinfection Accidental autoinoculation to self or others occurred due to pruritis and led to skin lesions, mucosal lesions, keratitis, burns, and eczema vaccinatum. Hand to hand and bathing can transmit vaccine virus. Treatment with VIG was 0.6 ml/kg for most lesions. Doses of 1-5ml/kg used for eczema vaccinatum. Generalized vaccinia generally benign. Gave 0.6 ml/kg of VIG. Progressive vaccinia in immunologically deficient, primarily in disorders of cell-mediated immunity. Usually fatal. Post-vaccination encephalitis also occurred rarely. Many persons with potential vaccine contraindications. Eff Clinical Prac 2002:5:84-90 Questions and answers - weaponized, that is dried, aerosolized forms, were created by both the USSR and USA programs. Mostly people stay home when sick and not contagious until rash develops. Dryvax has a 18 month or 3 year expiration date and is stored in carefully controlled conditions so testing and extension of expiration date can be done; so giving a supply to each state is problematic. Vial size cannot be reduced below 100 doses due to ensuring proper amount in each vial. Vaccinia vaccine is available only under Investigational New Drug protocol as they are not currently licensed. The risk of terrorist release of smallpox is considered low. Currently, there are enough VIG doses to treat about 600 serious adverse events. This is enough VIG to treat adverse reactions expected from vaccination of 4 to 6 million persons. 15 million doses of Dryvax that can be diluted 1:5 so 75 million doses diluted. Acam 1000 tissue based vaccine 54 million doses under contract for later in 2002-2003. 86 million doses Aventis vaccine. Acam 2000 tissue based vaccine 155 million doses under contract. Limited supply of VIG now and contract being negotiated. ACAM 1000 is grown in 9 passages in the MRC-5 cell line and the seed comes from Dryvax lots. ACAM 2000 is grown in vero cell line and should be produced by October 2002. Plan is enough vaccine for “all Americans” by the end of 2002 or shortly thereafter. Vaccine can arrive within hours of notification and can be delivered by CDC smallpox response teams. Additional vaccine should be available within 12 hours. Plan is to be able to deliver 75 million doses within 24-36 hours in “Vaxicool” self contained shipping units ready for rapid deployment. Vaccine is stored at multiple locations within US. Goal is to have delivery 280 million doses deployable in 5 days. To justify risk of vaccination in hospital setting, have to have risk of release (attack) of 1 in 100, 1000 cases before outbreak identified, and risk of contact 1:100 to 1:1000; actually, risk of contact is much less. For general public, risk of vaccine always outweighs disease, given risk of serious side effects of 1 in 100,000. For smallpox investigation team, assume risk of contact 1 in 5 then vaccination justified. In the US, 4.3 million health care workers of which 2.2 million are RNs. In health care settings, are 11.4 million workers. In ERs, 32,000 physicians and 89,000 nurses. Contact and respiratory isolation are recommended. Many physician misperceptions. Public had many misperceptions. In the Harvard Public Opinion Poll, 59% would get pre-exposure vaccination if available. Dr. Millar, a previous secretary for ACIP and worker in the field with smallpox eradication, noted a failure of the public health team in India that led to unnecessary blindness in a child. He believes that the government could develop a quantitative estimate of risk. He believes that there is incongruency between the government asking for major bioterrorism funds yet not providing vaccine to the public. Dr. Scott pointed out the issue of deferral of blood donors temporarily due to receipt of live viral vaccines and pointed to the need to keep a supply of donor blood. On question 1, agreement not to vaccinate the public. On question 2, no consensus. On question 3, agreement with the ring strategy. Many felt that this should be supplemented by vaccination of medical personnel. Little support for community vaccination. 91% favored option 1 to question 1. 77% favored option 2 to question 2; 16% favored option 3; 7% option 1. On question 3, 11% favored option 1, 36% option 2, 30% option 3, 18% option 4. Little support for mass vaccination. Some support for health care worker vaccination. Feeling in New York that patients went to the closest hospital regardless of disaster plans and that they demanded antibiotics after anthrax attacks. Feeling that local or state stock of vaccine should be available. Stan Plotkin asked that more research on aerosolized anthrax, including virulence, syndromes, and impact of dose. Pox viruses can be manipulated genetically. Smallpox contains genes that dampen host immune response. He also suggested that a better vaccine is needed. William Tell, speaking as a parent and citizen, urged permissive widespread vaccination of the public. Kathy Williams, speaking for NVIC, opposes widespread vaccination of the public. Dr. Tenpenny, an ER physician and NVIC member, spoke against widespread vaccination. Dr. Goldsmith, from the Immune Deficiency Foundation, spoke of concerns about fragile populations that could suffer if vaccination started and the need to carefully screen for immunodeficiencies if a program is started. Dr. Hinman, a former ACIP secretary, recommends option 1 to Q1, option 2 to Q2, and, to Q3, community vaccination in outbreak areas. 1971 Russian outbreak of 10 cases from weaponized form. 3 of 10 were hemorrhagic and died. The boat was 15 km from the island where aerosolized smallpox was being tested. 7 of the 10 had been vaccinated and did not die. 3 generation of cases occurred. Only 1 person was affected by aerosolized form. Only 1 person of the 12 crew members acquired the disease. A nearby natural outbreak in Asia occurred at the same time and might have been the cause of the outbreak instead of the weaponized form. One outbreak occurred in a hospital in Germany from aerosolized smallpox from a case with the flat variety. The occurrence of flat and hemorrhagic varieties suggest that host factors may be more important that strain differences. For the flat form, many of the deaths appeared to occur in persons with extensive skin lesions akin to third degree burns. The data were reviewed from multiple sources. Death estimated in 0.8 to 1.1 per million vaccinees and 0 to 0.2 per million revaccinees. 12.5% of deaths in contacts. Encephalitis occurred in 1.9 to 2.9 per million primary vaccinees and none among revaccines. State surveillance data showed higher rates at 3.4 to 12.3 per million vaccinees. For a hypothetical city of 3.5 million with 60% susceptibles, assuming 90% cases identified, 75% contacts identified, 75% contacts intervened, and number of secondary cases was 5 per initial case, one to two cases per week would be prevented by mass pre-event vaccination of 50%. The amount of control could be achieved by vaccination of a second ring equals that of vaccinating 30% of the general population. Tom Mack suggested that these 75% estimates were low– it would be closer to 99%. The economic costs are large. Differences in economic costs dominate differences in costs of vaccination. Implication: Benefit-cost analysis suggests strong consideration of broader pre-attack vaccination. Shut-down of the transportation system has a major cost of $41 billion per week or higher. Reduced consumer and business confidence would cost $4 billion per week. If probability of attack is very low, then no vaccination best. If low probability, then first responders including both public health and economic first responders. If moderate risk, then general voluntary vaccination. Never low-cost to vaccinate only public health first-responders. They think that pre-exposure vaccination merits strong consideration. Economic first responders (e.g., transportation workers (truckers, pilots, train engineers)) are important. Under current circumstances, with no confirmed smallpox and the risk of an attack assessed as low, vaccination of the general population is not recommended, as the potential benefits of vaccination do not outweigh the risks of vaccine complications. Smallpox vaccination is recommended for persons pre-designated by the appropriate bioterrorism and public health authorities to conduct investigation and follow-up of the initial smallpox cases that would necessitate direct patient contact; these persons are called a Smallpox Response Team. The ACIP recommends that each state and territorial plan establish and maintain at least one Smallpox Response team. Smallpox vaccination is recommended for selected personnel in facilities pre-designated to serve as referral centers to provide care for the initial cases of smallpox. These facilities would be pre-designated by the appropriate bioterrorism and public health authorities, and personnel within these facilities would be designated by the hospital. As outlined in the CDC Interim Smallpox Response Plan and Guidelines (www.bt.cdc.gov/DocumentsApp/Smallpox/RPG/index/asp), state bioterrorism response plans should designate initial smallpox isolation and care facilities (e.g., type C facilities). Workgroups are being formed on HIV vaccine and HPV vaccine. Resumption of routine vaccination can now begin. Aventis stated that they can supply half the DtaP market with the licensure of their Canadian DtaP here. PCV supply shortages remain. The fourth dose of PCV is to be deferred until the shortage is over. The projections for vaccine supply are 92-97 million doses, above previous years. Erratum is planned on timing to note that children aged 6 months - <9 years receiving the vaccine for the first time and household contacts of persons at risk are recommended for vaccination in October, in addition to persons at risk for complications, persons >/=65, and health care workers. The 2001 influenza season was mild to moderate. About 13% were B viruses and peaked later in the season. H3N2 peaked earlier and little H1N1 occurred. ACIP passed a motion adding healthy children aged 6-23 months for VFC coverage. The 2003 draft schedule was presented. The few changes include extending the Td bar to 18 years as the vaccine supply is adequate, clarifying the hepatitis B footnote, and adding influenza vaccine at ages 6 to 23 months to the footnote. Respectfully submitted, Richard K. Zimmerman, M.D., M.P.H. |
| This report is from the personal notes of
Dr. Richard Zimmerman and is not the official minutes of the ACIP meeting. These notes are provided only as an assistance for educators. As such, they cannot substitute for the individual judgment brought to each clinical situation by the patient’s physician. Official policies enacted later may differ from personal notes taken during a meeting. Clinicians should await official, published policies for the final recommendations. |
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LEGAL ADVICE. THE DECISION WHETHER OR NOT TO VACCINATE IS AN IMPORTANT AND
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YOUR HEALTH CARE PROVIDER.