Public Health/Flu shot


Ann, I've heard that flu immunizations each year are pretty much guesswork. I also read that the influenza strain going around this year has not been seen previously. Doesn't that make my flu shot worthless, since they apparently made vaccine for a different strain this year? Thanks for your time.

Hi Ed,

This is a great question! The Centers for Disease Control and Prevention (CDC), the Food and Drug Administration (FDA), and the World Health Organization (WHO), in collaboration with other researchers, collect and analyze influenza samples from all over the world each year to determine which strains have the highest potential for causing infection in the pending season. As the influenza virus has the potential and the propensity to mutate at any given time, it is difficult to pinpoint the exact strain(s) that will cause infections from year to year. Influenza vaccines that are administered each year are what are known as trivalent vaccines. This means that each vaccine given contains the three predominant strains of influenza virus that are affecting humans. Each vaccine is manufactured and distributed according to hemisphere. For example, the U.S. receives the vaccine which is likely to be the most effective for the Northern Hemisphere. The 2012-2013 vaccine for the Northern Hemisphere contains the following strains: A/California/7/2009 (H1N1)pdm09-like virus, A/Victoria/361/2011 (H3N2)-like virus, and B/Wisconsin/1/2010-like virus (from the B/Yamagata lineage of viruses). Influenza A H3N2 is currently the most common strain. While it is not new, it is highly virulent. Fortunately, the vaccine combination for this season is a strong match.

Getting the influenza vaccine each year is the best choice, especially if you or your family members are at high risk for exposure or have health issues. While many people may carry antibodies from previous vaccines or actual infection, receiving the most current vaccine is recommended. This is something that should be discussed with a health care provider to ensure that the appropriate course of action is taken for each individual.

In the event that you suspect you may have influenza, antiviral treatments can be administered but must be done so at the initial onset of symptoms to be the most effective. The most effective antiviral medications are Oseltamivir and Zanamivir. The antiviral medications Amantadine and Rimantadine may not be effective against the current influenza strains due to high levels of resistance shown by 2009 Influenza A H1N1 and Influenza A H3N2 and they are known to be ineffective against Influenza B strains.  Your health care provider will make the most appropriate choice according to your individual needs.

Some other suggestions (and under the supervision of a health care provider) that will help to boost your immune system are: get plenty of rest, drink plenty of fluids, exercise, have a well-balanced diet, and supplement with vitamins as needed (especially Vitamin C). Other good practices would be to wash your hands as often as possible (or use hand sanitizer if necessary), avoid crowded areas (as much as you can), cough into your elbow instead of your hand, wear an N95 mask, and stay home if at all possible when you are ill.

Thank you so much for your question. Please let me know if I can be of further assistance.

Dr. Ann

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Ann Herring MacLeod-Lambert


Categories of questions would include: Epidemiology (Humans and Animals), Disease transmission, Zoonotic diseases (diseases transmitted from animals to humans), Epizootic diseases (epidemic diseases in animals), Enzootic diseases (endemic diseases in animals), Precautions to use to avoid disease transmission and infection, Standard diagnostic and treatment protocols in use for infectious diseases (humans and animals), Health implications, Biosecurity (humans, animals, products, facilities), Precautions and risks for travel, Food safety, Environmental health.


Over 25 years of experience in veterinary medicine and science. I have worked in veterinary practice, served 10 years as a state veterinary epidemiologist and pathologist (livestock, equine, food safety, biosecurity), performed wildlife disease research, worked as a consultant, and provided educational presentations and materials for organizations and individuals. My specialties are zoonotic, enzootic, and epizootic diseases.

Degrees in Veterinary Medical Science, Biology, and a PhD (ABD) in Public Health Epidemiology (Veterinary and Human).

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