The estimated rate of anaphylaxis in young women after human papillomavirus
(HPV) vaccination was significantly higher - 5 to 20 fold - than that
identified in comparable school-based vaccination programs, according to a
study published in *CMAJ* http://www.cmaj.ca/press/179_6_525.pdf. However,
the overall rates of anaphylaxis were low with no associated serious lasting
effects.
In a study of 114,000 women, a team of Australian researchers found 12
suspected of anaphylaxis, and confirmed 8 of these, in a 2007 vaccination
program in New South Wales, Australia. Symptoms included difficulty
breathing, nausea and rashes.
Dr. Julia Brotherton and colleagues postulate that reasons for an increased
rate of anaphylaxis may include possible allergic reaction to the vaccine
components, enhanced adverse event surveillance, higher rates of anaphylaxis
in women from midadolescence compared with men, and an apparent increase in
incidence of anaphylaxis in Australia.
The estimated rate of anaphylaxis following HPV vaccination was 2.6 per
100,000 doses administered compared with a rate 0.1 per 100 000 doses
administered in a 2003 school-based meningococcal C vaccination program.
HPV vaccination programs will begin this fall in the United Kingdom and
other European countries as well as in parts of Canada and the United
States.
Dr. Brotherton stresses "the importance of good training for staff
administering vaccines in school or other settings in the recognition and
management of suspected anaphylaxis and its reporting." They conclude that
anaphylaxis following the HPV vaccine is rare and vaccine programs should
continue.
Anaphylaxis is a rare but serious adverse event and highlights the
importance of vaccine safety studies after vaccine licensing and careful
management of reactions in immunization clinics, says Dr. Neal Halsey,
Institute of Vaccine Safety, Johns Hopkins Bloomberg School of Public Health
in a related commentary http://www.cmaj.ca/press/179_6_509.pdf. He states
"before concluding that the HPV vaccine is associated with higher rates of
anaphylaxis than other vaccines everywhere, cases in other populations
should be reviewed….As of July 21, 2008, 11 cases have been reported [in the
US] in 2008. Over 13 million doses of this vaccine have been distributed as
of the end of 2007."
A *CMAJ* editorial http://www.cmaj.ca/press/179_6_503.pdf states that this
study indicates the HPV vaccine is "remarkably safe." The study provides an
excellent opportunity for Canada's public health community "to restart
public discussions about the safety of the HPV vaccine, the precautions
taken to mitigate risks if anaphylaxis occurs, and the care taken in
surveillance for adverse events following vaccination," write Drs. Noni
MacDonald, Matthew Stanbrook and Paul Hebert.
0 comments
Post a Comment