Is the H1N1 Vaccine Safe?

Is the H1N1 vaccine safe? I've heard this question a lot since I began promoting the book I co-authored, The Complete Idiot's Guide to Vaccinations. Young adults and mothers of young children tend to ask me about the H1N1 vaccine, because they are weighing the risks and benefits of getting vaccinated.

Modern vaccines are extremely safe. Problems such as bacterial contamination of vaccines, a serious threat several generations ago, has been largely eliminated through the use of preservatives and improved packaging. Many older vaccines have also been reformulated to reduce the risk of side effects (such as the old DTP vaccine, and the earlier rotavirus vaccine for children).

The H1N1 vaccine is made in the same way as the seasonal flu vaccine. The viruses that cause the flu are grown and biologically weakened in chicken cells, until they are still strong enough to create an immune system response in people, but too weak to cause the disease in a healthy person. Then the weakened viruses are either:

• killed and used in the seasonal or H1N1 flu shot (the best choice for people with weakened immune systems or other risks), or 
• kept alive and used in the seasonal or H1N1 flu nasal spray vaccine (the best choice for certain people with healthy immune systems).

The seasonal flu shot has been available since the middle of the last century; the nasal spray flu vaccine was licensed in the United States in 2003.

The CDC tracks health problems that might be linked to vaccines with the Vaccine Adverse Event Reporting System (VAERS). Both health care providers and the general public can report health problems that occurred after a vaccination to VAERS. Researchers monitor VAERS, looking for patterns of problems with a vaccine. If a pattern does occur, then they do further research within the Vaccine Safety Datalink (VSD), a database containing the health records from eight managed-care organizations across the country.

What have they found since they have been tracking the H1N1 flu vaccine? The CDC's Dec 11 Morbidity and Mortality Weekly Report (MMWR) found that the risk of serious side effects (adverse events) from the H1N1 vaccine is about the same as the risk for the seasonal vaccine. In a word: low. From October through November 2009, VAERS data showed 82 adverse events per million doses of H1N1, and 47 adverse events per million doses of seasonal flu vaccine.

Still, the rumors are flying about the H1N1 vaccine: that it can cause Gulf War Syndrome or Guillain-Barre syndrome, that it contains Agent Orange, and so on. The website FactCheck.org's "Inoculation Misinformation" article provides a good overview and rebuttal of some of the questions that have cropped up in emails and online about the H1N1 vaccine.

ABC, the AAP, and Autism

I've been thinking a lot about the American Academy of Pediatrics’ recent protests of the January 31 pilot episode of the ABC television show “Eli Stone.” In the lawyer drama, a mother receives a $5.2 million settlement after she charges that the mercury-laden preservative thimerosol that was used in a vaccine caused her child’s autism. Since many children are diagnosed with autism around the time that they receive a number of vaccinations, some people have linked these vaccinations with autism, especially the MMR (measles, mumps, and rubella) vaccination.

A small but influential 1998 study suggesting a link between thimerosol and autism was later retracted by its authors, and researchers have since found no link between vaccinations and autism. Furthermore, thimerosol was dropped as a preservative in standard vaccines in the U.S. in 2001.

Some parents still refuse vaccinations for their children, though, due to concerns about vaccine contents and the possibility of rare complications. Their choices have lead to regional, sometimes fatal outbreaks of measles and whooping cough (pertussis) among unvaccinated children. Right now, for example, there is a measles outbreak in San Diego, with ten unvaccinated children and infants infected and over fifty quarantined.

The AAP only fueled the vaccination debate, however, with an emotional press release in late January, calling the “Eli Stone” pilot “the height of reckless irresponsibility.” In the letter, AAP President Dr. Renee R. Jenkins says that “if parents watch this program and choose to deny their children immunizations, ABC will share in the responsibility for the suffering and deaths that occur as a result. The consequences of a decline in immunization rates could be devastating to the health of our nation’s children.” The AAP went on to authorize the early release of a February Pediatrics journal article showing that infants expel the type of mercury used in thimerosol over ten times faster than they expel the type of mercury often found in fish. Some researchers believe that if heavy metals such as mercury build up in the body, they might cause autism.

But what this debate really comes down to is parents’ fear of autism, a fear that is especially acute in the San Francisco Bay Area where I live. A CDC study released in 2007 that looked at autism spectrum disorders in selected regions of the country found an average rate of autism of about 1 in every 150 eight-year-old children. Earlier estimates had suggested autism was much less prevalent, as low as 1 in 500 children. The CDC pointed out that it’s unclear whether the autism rates are increasing over time, or whether it is simply being diagnosed and reported more accurately.

Still, no one knows what causes autism, and a quick glance at the numbers makes it look like an epidemic. When I had my first child, I, too, was told by well-meaning acquaintances that mercury-laden vaccinations might cause autism, one of a long list of things to panic about as a sleep-deprived new Mom. If I had my child vaccinated and she developed autism soon thereafter, would it be my fault if the light in her mind dimmed? Was I willing to take that chance?

By the time my children were born, though, thimerosol had been pulled from the vaccines, and pertussis was making an alarming comeback in San Francisco among unvaccinated infants and adults whose pertussis vaccinations had worn off. My children were vaccinated.

There is a frightening childhood illness for every generation, it seems. At one time it was polio, until Jonas Salk developed an effective vaccine for it in the 1950s. My great aunt had polio as a young woman (luckily she recovered fully). My mother, who grew up in the Bay Area, remembers driving by San Francisco’s Shriner’s Children’s Hospital on 19^th Avenue with her family, where many of the young polio patients were dependent on iron lung machines, wondering if that would happen to her. Today, the old Shriner’s Hospital is a retirement community next to a row of modern townhouses, and thanks to the vaccine polio is almost completely eradicated worldwide.