LANSING - MedImmune, the maker of the nasal spray monovalent 2009 H1N1 flu vaccine, is recalling about 4.7 million doses of the product because the potency has slightly decreased. Michigan has received more than 114,000 doses of the vaccine. Health departments, clinics or private doctors' offices across the entire state of Michigan received the recalled doses. There are no safety concerns with these recalled batches of the vaccine.

While the antigen content of these doses is now below the specification limit for the product, the Centers for Disease Control and Prevention and the Federal Drug Administration are in agreement that the small decrease in potency is unlikely to result in a clinically significant reduction in immune response among persons who have received the vaccine. For this reason, there is no need to revaccinate people who have received vaccine from these batches.

Providers are being asked to return any vaccine that remains unused to the manufacturer from the specified lots. The CDC also notes the following:

- All doses successfully passed pre-release testing for purity, potency and safety.

- There is no need to re-administer a dose to those who received vaccine from these batches. The vaccine potency is only slightly below the "specified" range. The vaccine in these batches is still expected to be effective in stimulating a protective response despite this slight reduction in the concentration of antigen.

- All children less than 10 years old should get the recommended two doses of H1N1 vaccine approximately a month apart for the optimal immune response. Therefore, children less than 10 years old who have only received one dose of vaccine thus far should still receive a second dose of 2009 H1N1 vaccine.

The Michigan Department of Community Health (MDCH) encourages residents to get the H1N1 vaccine as it is available to everyone in the state. In addition to being vaccinated, Michigan residents can help stop the spread of the virus by washing hands thoroughly and often; covering mouths when sneezing or coughing; and staying home from work or school if sick.

For more information on vaccine availability, check the MDCH Web site at www.michigan.gov/flu. You can also follow MDCH on Facebook and Twitter by going to the Web site. Also, call your local county health department or 2-1-1 public information hotline. If 2-1-1 doesn't work in your area, you can call 866-561-2500 or 800-552-1183. For more information on the recall, please visit www.cdc.gov.