Adverse events reported for HPV vaccine

As 4 provinces began immunizing schoolgirls to prevent the human papillomavirus, a watchdog group in the United States warned of dangerous adverse events stemming from the vaccine's delivery — concern government regulators dismiss.

Public health officials in Ontario, Nova Scotia, Prince Edward Island and Newfoundland and Labrador began administering the Merck Frosst vaccine Gardasil to select groups of girls (grades 6, 7 or 8) in September, just as the US advocacy group Judicial Watch released documents obtained through Freedom of Information indicating that 3 deaths and 1637 adverse events occurred after the vaccine was administered (prior to May 15).

Judicial Watch acknowledged, however, that it did not analyze the adverse events data from a medical perspective. “We wanted to get the information out in a public light. … It's out there for people who know more than us to interpret,” program manager Dee Grothe said, adding that the organization's main concern is that the vaccine not be mandated by state governments.

The adverse events data comes from the US Food and Drug Administration's Vaccine Adverse Event Reporting System. According to the Centers for Disease Control and Prevention in Atlanta, as of June 30, there were 2531 adverse reports, including 9 deaths, out of 7 million doses dispensed. The figures, however, can include multiple reports of the same event, since physicians, manufacturers and patients report to the same system.

Health Canada, meanwhile, received 82 adverse event reports out of 162 000 doses distributed as of Aug. 17. Five adverse events required hospitalization, including 2 later determined to be appendicitis. One patient fainted, 1 event appears related to a viral infection, and 1 appears related to encephalopathy, which Health Canada is investigating.

“This is not unusual,” says Dr. Theresa Tam, director of the Public Health Agency of Canada's Immunization and Respiratory Infections Division. “Every new vaccine that comes on the market, people monitor the safety profile, and inevitably, there are things that occur following immunization.”

Neither the product monograph nor permission forms that parents (in Ottawa, for example) receive from local public health authorities contain a list of possible adverse events, such as deaths, following administration of Gardasil.

Although Canadian authorities are aware of the US reports, the deaths are not listed as possible adverse events because there is no scientific evidence proving a causal relationship with the vaccine, says Tam. “At this point, there is nothing that I can see that is of particular concern. … It's what we probably would expect to see based on the clinical trials and the background rates of some of these conditions.”

Centers for Disease Control and Prevention spokesman Curtis Allen says all deaths and other serious adverse events requiring hospitalization are investigated. The agency has classified 5% of vaccine-reported events as “serious.” The most common reactions have been pain at the injection site, general pain, nausea, dizziness and fainting. The incidence of fainting is slightly higher than the background rate normally expected among that age group, Allen says. As a result, “we're suggesting that physicians keep patients in their office for 15 minutes after administering the vaccine.”

Some of the 9 deaths were duplicate reports, while 1 patient turned out to be “very much alive,” Allen added. There are 4 confirmed deaths in girls or women who received the HPV vaccine, but it is not known to have caused any of those deaths.

In 2 cases, women died after suffering pulmonary embolisms, but they were also taking birth control pills, a known risk factor, says Allen. In 2 other instances, girls had influenza, and myocarditis resulted in the death of 1 of those patients.

“The deaths do not appear to be connected at all with the vaccine,” Allen says. “It appears to be a very safe and effective vaccine and we believe it's very important to women's health.”

Sheila Murphy, a spokesperson for Merck Frosst in Canada, says the company's worldwide database on adverse events, which is shared with regulators, does not indicate there's a need for a change in the product monograph or “some kind of an announcement. … There are always adverse events with anything, whether they're related to the product or not is always the question.”

Murphy says there's been intense media attention surrounding the vaccine “because it's about sex. And also cancer.”

As HPV vaccines are administered to girls who are not yet sexually active and haven't been exposed to the virus, critics fear it confers tacit approval of premarital intercourse. Others worry that vaccination will reduce Pap test screening or will prove ineffective over time. Still others question the vaccine's value for money.

Concerns have also been expressed about Merck's political influence, having hired lobbyists well-connected to Prime Minister Stephen Harper and Ontario Health Minister George Smitherman. The federal government provided $300 million in the last federal budget for provincial vaccination campaigns.