H1N1 Immunization
As the H1N1 epidemic evolves, it is now time to move into vaccination. There is much confusion and contradictory information out there; and rightfully so, since things are moving fast and it’s hard to keep up with the literature. The following is a summary of some of the questions we have been getting recently. If there is more that you need to know, please contact us.
Is the H1N1 vaccine safe? Has it been fully tested?
The seasonal flu changes every year. That is why the vaccine has to be re-formulated and that is also why healthcare workers and the public must receive a new version of the flu vaccine every year. But also, because of the limited amount of time, the new version of the vaccine goes through limited testing for FDA approval. After so many years of going over this process, FDA and other regulatory agencies have learned what properties a flu vaccine must have in order to be considered safe and effective.
The H1N1 is another version of the process. It’s made under the same conditions, by the same companies and has gone through the same evaluation and approval process as the seasonal flu vaccine. So, based on years of experience, there is no reason to anticipate any different (worse or better) result from the H1N1 vaccine. And that applies to the two versions of the vaccine, the nasal-spray and the injectable.
Therefore, anyone who normally receives seasonal flu vaccine or anyone for whom seasonal flu vaccine is routinely recommended should also consider H1N1 vaccine; for both versions there is the same level of recommendation. As with all vaccines, immunization is voluntary but, by all means, strongly recommended.
How effective is the vaccine?
Because the epidemic is still evolving, we still don’t have full data on the effectiveness of the vaccine. However, the level of antibodies that the vaccine induce suggest that it will be rather effective in preventing H1N1 influenza. Actually, since the H1N1 virus has not changed yet, it may happen that the H1N1 vaccine works better than the seasonal flu vaccine. Of course, it will not protect against other influenza viruses or against other viruses that may circulate during the fall and winter.
Where to get H1N1 vaccine?
Only registered providers will be able to receive and administer H1N1 vaccine. To find a complete list of providers that will be giving H1N1 vaccine check www.flula.com.
What H1N1 vaccine is better?
There are two forms of the vaccine: the nasal-spray vaccine and the injectable vaccine (for more information on each product, visit FDA’s website at http://www.fda.gov/BiologicsBloodVaccine/vaccines/ApprovedProducts/ucm181950.htm). Both types are equally effective in preventing H1N1, but they are indicated for different populations. The nasal spray can be used in healthy individuals 2-49 years of age. It is not recommended for pregnant women, children with asthma, healthcare workers, persons with immune problems and persons 50 years and older. The injectable vaccine can be received by healthy individuals as well as the groups noted above. The nasal-spray vaccine has already been distributed and the injectable vaccine will come soon. There are four different injectable vaccines and they each have different age indications; make sure you use the correct one. Some vaccines (multi-dose) contain thimerosal and some (single-dose) don’t.
Will there be priority groups for vaccination?
Vaccines will be available in incremental numbers. Because the number will be limited at the beginning, some prioritization seems advisable. However, the emphasis is in immunizing as many as possible as soon as possible. The five priority groups are: pregnant women, persons who live or provide care for children younger than 6 months, healthcare personnel, children and young adults 6 months to 24 years, and persons 25 to 64 years who have medical conditions that put them at higher risk of complications from influenza. Within those groups, and depending on vaccine availability, you may further prioritize, for example, pregnant women (remember only injectable for them), children 2-9 years (because they will need two doses), children of all ages with high-risk conditions, parents and caretakers of children < 6 months, children and adolescents, older persons, etc. But, if you are seeing a child that does not fall into one of these categories but wants the vaccine, you are free to give it. Keep in mind that when more vaccine is available, school-based vaccination campaigns will be initiated in both public and private schools.
One or two doses?
Children under 10 years of age will need two doses, four weeks apart. Children 10 years and older will need one dose only.
What if my patient had H1N1, does he still need vaccination?
There is no good answer for this question. First, you would have to be completely sure it was H1N1. Even during the worst of the epidemic we have seen only ~25% cases testing positive for Flu A. Because the test is less than perfect, some of the others may be missed by the test or were other viruses. And, even if it was Flu A (most of which were H1N1), children under 10 still will need two doses, so likely the child would still need a second dose.
Is it still worth trying vaccination?
The number of cases of flu – the vast majority of which are H1N1 – seems to be decreasing in the area. It feels that in Louisiana the epidemic is over and the vaccine may be arriving too late. While that may be true, that is impossible to know at this time. Equally likely is that the epidemic may recrudesce as the weather changes or that a second wave of disease may occur later in the year. In previous epidemics, second waves have been worse than the initial one. So, the virus may be gone or may be just taking a break and return stronger. In any event, it does not seem wise to take chances. It is more advisable to immunize the population so a second wave has less chance to spread and if so, it has less chance to cause severe disease, especially among the vulnerable population.