Use of the vaccines, which protect children against bacterial infections that can lead to meningitis and pneumonia, was suspended late last week until a safety panel could meet to examine the cause of the deaths. The panel found no connection between the vaccines and the deaths, but it said further study was needed, Reuters reported. The committee will schedule another meeting to review additional data before making a recommendation on resuming vaccinations, according to Pfizer. The company added that it expects vaccinations will resume soon.
Sanofi-Aventis's ActHIB vaccine protects against haemophilus influenzae type b (Hib), one of the most common causes of bacterial meningitis, an infection of the covering of the brain and spinal cord. Pfizer's Prevnar vaccine (also sold as Prevenar) protects against pneumococcal bacteria that can cause ear infections, meningitis and pneumonia, among other things.
The four children, ranging in age from 3 months to 2 years, were administered Prevnar, and all except one received ActHIB at the same time. In addition, three received other vaccines on the same day. Three of the four children died a day after being immunized. Three of the deaths occurred last week.
Timing of Deaths Was Coincidental
In the U.S., both vaccines are part of the recommended childhood immunization schedule for children under 5 years old, according to the Centers for Disease Control and Prevention, and are widely used. According to Sanofi, more than 130 million doses of its hib vaccine have been distributed in the U.S. since it was licensed in 1993.
"To date, physicians assessing vaccine safety at the FDA and CDC have not detected new safety concerns. . .among children vaccinated in the U.S. CDC and FDA will continue to monitor the safety of all vaccines, including [ActHIB and Prevnar] vaccines."
According to Forbes, experts in vaccine research say that in all likelihood, the deaths in Japan were coincidental, and that the Japanese health ministry acted too rashly.
ActHIB, Prevnar Prevent Thousands of Deaths Annually
The companies say they're cooperating with the Japanese government. "Pfizer supports the health ministry's conclusion that there is no evidence of a causal relationship to vaccination in these cases," a Pfizer spokeswoman told DailyFinance in an emailed statement. "Pfizer has also thoroughly and extensively examined these cases and all available data ... and has concluded that Prevenar meets all standards for distribution and use in Japan and in all countries where it is available."
"Sanofi Pasteur is fully collaborating [with the investigation]," a company spokeswoman told DailyFinance in an emailed statement. "No causal relationship has been established between immunizations and these fatalities."
According to Sanofi, since ActHIB's launch in 2008, it has been administered to an estimated 1.5 million people in over 3 million doses in Japan, while Pfizer Japan has distributed more than 2 million doses of Prevnar in that country. Worldwide, more than 200 million doses of ActHIB have been administered to children in over 120 countries, and Pfizer has distributed more than 360 million doses of Prevnar in more than 100 countries.
While vaccines can have rare, and usually mild, side effects, the diseases they prevent can lead to deaths. For example, 5% of children younger than 5 years old who contract pneumococcal meningitis will die of the infection, and others will have long-term problems such as blindness or hearing loss, according to CDC. Before the Hib vaccine, about 20,000 children in the U.S. under 5 years old got severe haemophilus influenzae type b each year, and nearly 1,000 people died from it annually.