by Amy Spangler
November 04, 2009

Fears over vaccine safety are causing many people to adopt a wait and see approach with regard to the H1N1 vaccine, raising concerns that the H1N1 flu pandemic will be even more widespread.

In an effort to address these concerns, the Department of Health and Human Services (DHHS) held a webcast on October 14, 2009.  The hour-long program featured Dr. Bruce Gellin, National Vaccine Program Office (NVPO), Dr. Jesse Goodman, Food and Drug Administration (FDA), Dr. Harvey Fineberg, Institute of Medicine (IOM), and Rear Admiral Anne Schuchat, Centers for Disease Control and Prevention (CDC).

Vaccine development, vaccine composition, and vaccine safety were among the topics discussed, including reports that the H1N1 flu vaccine was distributed before adequate testing was done. Among the clinical trials was one involving a group of 50 pregnant women who were given a single 15-microgram dose (a minuscule amount) of the H1N1 vaccine. Results showed that each woman produced a protective level of antibodies and none of the women experienced any adverse effects. Researchers cautioned that while these results are encouraging, until there is widespread use of the H1N1 flu vaccine in a pregnant population, complications that occur rarely may not show up. To ensure transparency with regard to safety, a panel of experts from outside the government has been asked to monitor vaccine recipients for rare or unexpected side effects. The panel is scheduled to meet every two weeks and report monthly.

Dosage & additives
While one dose appears to protect pregnant women, two doses given a month apart are recommended for children ages 6 months to 10 years. The World Health Organization (WHO) recommends a single dose for all children. However, its recommendation is based on a need to make limited supplies of the vaccine available to the greatest number of children worldwide. The U.S. is focused on protecting U.S. children only and therefore recommends two doses.

Concerns have also been raised regarding vaccine additives. In response, U.S. health officials have decided to fore-go the use of adjuvants—materials (oils or salts) that when added to vaccines increase their effectiveness and allow for smaller doses to be administered.  Adjuvants are widely used in Europe and Canada and are thought to be safe. However, anti-vaccine lobbyists in the U.S. have campaigned against their use. Concerned that some Americans would refuse vaccines containing adjuvants, U.S. health officials decided not to use them.

Does breastfeeding protect newborns?
It is unclear what level of protection breastfeeding gives to exclusively breastfed infants of vaccinated mothers. While antibodies formed in response to the vaccine are transferred through human milk, no one knows if the level of antibodies is sufficient to keep breastfed babies from developing the H1N1 flu. However, any amount of protection is beneficial, so mothers are encouraged to breastfeed.

Currently there is no evidence that the H1N1 virus is transmitted through human milk. However, because the H1N1 virus appears to be more virulent (capable of producing disease and death) than other viruses, breastfeeding mothers who are extremely ill with the H1N1 virus are cautioned to follow specific guidelines set forth by the American Academy of Pediatrics (AAP) and the Centers for Disease Control and Prevention (CDC) in an effort to minimize the risk of infecting their baby while breastfeeding. If a mother is too ill to breastfeed, her expressed milk can be fed to her baby.

AAP guidelines
In an article published October 13, 2009 in AAP News, Drs. Lawrence and Bradley take a cautious but practical approach. They recommend that breastfeeding mothers infected with the H1N1 flu virus take the following precautions:

• Wash your hands carefully before each and every contact with your baby
• Wash your breast(s) with mild soap and water and rinse well
• Wear a surgical mask to reduce the risk of infecting your baby
• Use clean blankets and burp cloths each time you come into contact with your baby

These precautions should be followed until the mother no longer has a fever. They are designed to minimize the risk of transmission of the virus from mother-to-baby until the mother forms protective antibodies in response to the virus. The H1N1 flu virus does not pass through breast milk. However, the antibodies formed in response to the virus, do, providing protection for mother and baby.

While use of antiviral therapy in the mother and separation of mother and baby may be the most effective way to prevent mother-to-baby transmission, separation immediately after birth can interfere with mother-infant bonding and the establishment of breastfeeding. So consideration must be given to the benefits and the risks.

If a mother is infected with H1N1 and in labor, antiviral therapy is recommended such as oseltamivir (Tamiflu) or zanamivir (Relenza), and the recommendations listed above should be implemented. The amount of oseltamivir (Tamiflu) excreted into breast milk is so small there is no cause for concern.

Lawrence and Bradley acknowledge that there is limited data to support their recommendations, but believe these recommendations represent an appropriate balance between the benefits of breastfeeding for mothers and infants and the risks of mother-to-child transmission of H1N1 flu virus. They encourage institutions to modify the recommendations to meet their needs and medical practices.

CDC guidelines
Updated guidelines from the Centers for Disease Control and Prevention (CDC) can be found online in a document titled, “Guidance for Prevention and Control of Influenza in the Peri- and Postpartum Settings.”

The CDC recommendations are similar to those issued by Lawrence and Bradley on behalf of the AAP, with one exception. Citing insufficient data, the CDC declined to provide guidance on the use of antiviral drugs in pregnant women and new mothers.