The US Food and Drug Administration approved on Tuesday four H1N1 flu vaccines that demonstrated in clinical studies that a single dose produced a strong immune response in healthy adults after 8–10 days. Based on the manufacturers’ production schedules, things seem to be on track for vaccines to be available in four weeks.
But clinical trials of the vaccine are still underway on pregnant women and children, two groups that the Centers for Disease Control and Prevention (CDC) says are especially vulnerable to the H1N1 flu. CDC has identified five priority groups to receive the vaccine once it becomes available: pregnant women, people who live with or care for infants, healthcare and emergency medical services personnel, people between 6 months and 24 years old, and adults with chronic conditions ages 25–64. CDC estimates these populations total approximately 159 million people in the United States.
CDC’s Q&A document titled “2009 H1N1 Influenza Vaccine and Pregnant Women” says certain populations, including pregnant women, may need two doses. That will be confirmed when the data from the clinical trials are in. The National Institutes of Allergies and Infectious Diseases (NIAID) began the initial clinical study in pregnant women on Sept. 9, and it involves up to 120 women, ages 18–39, in their second or third trimester of pregnancy. Participants received an initial injection and will get a second shot 21 days later. Samples of the women’s blood and of the cord blood will measure the immune response and the presence of maternal antibodies crossing the placenta to the infants. NIAID plans to conduct studies at six medical centers nationwide.
FDA’s statement on Tuesday said that ongoing clinical studies of the vaccine in children will point to the appropriate dosage. The agency expects to know for sure “in the near future.”
Safety of the vaccine is a concern for pregnant women and parents. After all the efforts and recommendations of government agencies and vaccine manufacturers around the world, will pregnant women and parents want it? CDC says, “We do not expect that there will be a shortage of 2009 H1N1 vaccine, but availability and demand can be unpredictable.” What if the demand is significantly below what CDC is expecting?
A report on NPR Health Blog says that only about 15% of pregnant women get the seasonal flu shot, despite recommendations by CDC. “The swine flu vaccines are not specifically approved for pregnant women. But neither are ordinary seasonal flu vaccines. The reason, says FDA, is that the agency doesn’t specifically approve most adult drugs for categories of adults, such as pregnant adults,” according to the article, which also suggests that obstetricians do not urge their pregnant patients to get seasonal flu vaccines. Perhaps that is due to this text found on the vaccine labels, explains the article:
“If you look at the fine print on seasonal flu vaccine labels, you’ll see language like this: ‘It is not known whether (this vaccine) can cause fetal harm when administered to a pregnant woman or can affect reproduction capacity. (This vaccine) should be given to a pregnant woman only if clearly needed.’”
Without strong recommendations from their OBs, pregnant women may not want to line up to get the H1N1 shot when it becomes available.
Uncertainty about the safety of the H1N1 vaccine is evident on community message boards and on websites, such as the pregnancy-focused babycenter.com. In the “Swine Flu Discussion Group,” some moms-to-be are skeptical of the new vaccine, calling it “rushed” or “not tested enough” and generally calling into question the vaccine’s safety, given the speed at which it was produced, and effectiveness against the new form of the flu.
This week, a Los Angeles Times article reported that some parents refuse to vaccinate their children against H1N1, preferring them to catch the virus and develop a natural immunity. Physicians say that young parents could refuse the vaccine for their children for a number of reasons, including fears of a link between vaccines and autism, the fact that many of the parents grew up not knowing about once-common childhood diseases, wariness of a vaccine that is still being tested, and a “distrust of drug manufacturers, media outlets and the federal government,” according to the article.
People remain unsure about the H1N1 vaccine despite FDA’s and CDC’s reassurances that it is made by trustworthy manufacturers using established procedures. In this week’s FDA release, Jesse Goodman, FDA acting chief scientist, says, “The H1N1 vaccines approved today undergo the same rigorous FDA manufacturing oversight, product quality testing, and lot release procedures that apply to seasonal influenza vaccines.” The statement also pointed out that the four vaccine manufacturers “have a long record of producing safe seasonal influenza vaccines.”
Despite public uncertainty, the H1N1 shot is recommended as the best way to prevent catching the virus and avoid complications from it—in addition, of course, to proper hand washing and avoiding sick people. As CDC says in its Q&A document on the vaccine’s safety, “CDC and FDA believe that the benefits of vaccination with the 2009 H1N1 influenza vaccine will far outweigh the risks.”