Thimerosal is no longer used in routine vaccines for infants
in Canada and the U.S., but at one time almost every child in
B.C. received a vaccination that used the compound as a
preservative.
"About 95 per cent of children received it," said Dr. John
Blatherwick, chief medical health officer for the Vancouver
Coastal Health Authority.
Beginning in the 1970s, he said, every child who received a
mumps/measles/rubella (MMR) shot was exposed to Thimerosal.
"Most of the vaccines at one time or another had Thimerosal
in them," Blatherwick said, and it is still used in MMR shots
for children in Grade 6.
"It was a very good preservative," he said, adding that
scientific research has not drawn a clear link that the benefits
of using vaccines containing Thimerosal outweighed the risks.
"The over-all benefits of the vaccines was so overwhelming
that it would be malpractice not to give them," Blatherwick
said.
He suggested that the two lawsuits filed this week -- the
first in B.C. to claim a causal link between Thimerosal and
autism -- will have a hard time proving the cause and effect.
"The world literature says that's not true," he said,
referring to the allegation that Thimerosal can be linked to
causing autism.
But Vancouver lawyer David Klein, who is representing the
children and their parents in the lawsuits filed this week,
maintains the jury is still out on the issue.
"The science is still emerging," the lawyer said. "The
science is not definitive."
He said the rates of autism have increased dramatically over
the last 10 years and only in recent years have scientists
looked at the possible effects of Thimerosal.
"Our position in this lawsuit is that different children have
different levels of susceptibility," Klein said
That is, not every child who received vaccines with
Thimerosal would suffer neurological damage or symptoms of
autism.
Klein estimated that potentially hundreds of children could
join the class-action lawsuits, which are similar to two filed
in Ontario last year and more than 50 filed in the U.S.
"It may be in the thousands," Klein said of the potential
size of the action, which has yet to be certified by a judge.
The class action defines potential members as children born
on or after Jan. 1, 1980 who received vaccines containing
Thimerosal at the age of two years or younger.
The three brands of hepatitis B vaccines distributed in
Canada were Heptavax and Recombivax, made and distributed by the
drug company Merck Frosst Canada, and Engerix B, which was made
and distributed by GlaxoSmithKline Inc.
The other drug company named in the lawsuits is Aventis
Pasteur, which used to be known as Connaught Laboratories. It
changed its name after it was bought by Aventis in 1999, the
lawsuit says.
Connaught sold and distributed the vaccines Diphtheria/whole
cell Pertussis/Tetanus (DPT), Tetanus/diphtheria absorbed (Td)
and Diphtheria Tetanus toxoids pediatric (DT).
