H1N1 Vaccine Update: CDC versus the WHO

The Centers for Disease Control and Prevention (CDC) confirm that pregnant women and all age groups above 10 years will get sufficient protection from the 2009 H1N1 influenza with a single dose of the vaccine. The World Health Organization (WHO) has recommended that one dose of the vaccine is sufficient for children under 10, but the US will not follow this recommendation. The CDC is taking a more conservative approach to ensuring complete protection for children under 10 and recommends they receive 2 doses of the 2009 H1N1 vaccine four weeks apart.

Vaccinations are being produced around the world but production is slow, and distribution and administration of the vaccine is difficult. As expected the World Health Organizations primary goal is to ensure that the world’s vaccine supplies stretch as far as possible and recommend that priority be given to the administration of one dose of the vaccine to as many children as possible.

With this in mind the WHO has also endorsed the use of adjuvants to stretch the vaccine supply. Adjuvants are a substance that is added to the vaccine to increase the body’s immune response to the vaccine. This allows a smaller dose of the vaccine to work better. US public health officials were presented with a dilemma early in the vaccine production stage. Adjuvants have been used effectively in US vaccines for years that prevent hepatitis A, hepatitis B, diphtheria-tetanus-pertussis (DTP), Haemopilus influenza type b (Hib), human papillomavirus (HPV) and pneumococcus infection. But because the American public has become skeptical about the safety of childhood vaccinations federal health officials decided early in the development stage of the vaccine to not include adjuvants in the 2009 H1N1 vaccine.

The WHO’s expert panel also has recommended that pregnant women are safe to take the nasal-spray (flu-mist) of the vaccine which is a live version of the vaccine. US officials are taking a much more conservative approach and suggesting pregnant women only receive the killed shot version of the vaccine and get it as soon as it is available in their area. Pregnant women, people who live with or care for children younger than 6 months of age, healthcare and emergency workers and people between the ages of 6 months and 24 years of old, and anyone with a compromised immune system are priority groups for getting the 2009 H1N1 vaccine first.

Because the H1N1 virus has been around since the spring of 2009, many people are unsure if they have immunity to this illness. The CDC is taking a very conservative approach to this and suggesting that unless you had a laboratory test confirming that you had H1N1, it is advisable that you get the 2009 H1N1 vaccination when available. None of the Food and Drug Administration (FDA) rapid tests are currently approved to distinguish 2009 H1N1 flu from other flu viruses. Rapid tests that are done in an outpatient setting such as a physicians office are quick (results in 30 minutes) but their ability to accurately detect the flu virus can range from 10 — 70%. This means that some people with a 2009 H1N1 flu infection might receive a negative rapid test result (false negative test result). Only the real-time reverse transcriptase polymerase chain reaction test (rRT-PCR) confirms the 2009 H1N1 strain. This test is only available in certain laboratories, and these tests can take several days to obtain results. The CDC is focusing use of these tests on people who are hospitalized, very ill and in high risk groups such as pregnant women and people with weakened immune systems.

The National Vaccine Advisory Committee has launched an advisory group to monitor for any unexpected side effects from the 2009 H1N1 vaccine. This group will review results of data being collected by the government to detect any problems with the new vaccine as soon as possible.

The vaccine supply is in the distribution pipeline and is being delivered to allocated project areas. To date roughly 30 million doses of the vaccine are available. Of the 30 million available, the CDC reports that roughly 17 million have been shipped as of October 28, 2009. Click here to get State contact information on the availability of the vaccine in your state. To see the table for the vaccine shipment status as of October 28th, 2009 go to the CDC Vaccine Supply Table.

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