Chances are, at some point in your life, you have received a vaccine. But do you know how those vaccines actually work? When you get a shot, you are either injected with a dormant, noninfectious strain of the virus, to which your body develops immunity, or with components of the virus to which your body makes antibodies (a soluble defense system). If you come into contact with that virus after you have been vaccinated, your body recognizes it, and the antibodies work their magic to protect you from it. A flu shot is a component vaccine that leads to antibody production.
Every fall, people of all ages line up to get a flu shot to ward off illness. But the flu vaccine does not protect against every strain of the virus – only the strains that are considered prominent that particular year. Currently, in December 2018, there are two influenza A strains and two influenza B strains in circulation. However, each of those strains likely has variants, or sub-strains, and what’s circulating now won’t necessarily circulate next year. Immunity in 2018 does not guarantee immunity in 2019.
Vaccines are essential for protecting the general public from illness. Scientists have developed effective vaccines that prevent diseases like the measles and mumps; so, why isn’t there one vaccine that combats all strains of the influenza virus? Though a universal flu vaccine is a goal for many researchers, it’s easier said than done. According to Blood Research Institute Senior Investigator Jack Gorski, PhD, “The flu virus is easily mutable and keeps changing its coat. The antibody part of the immune system tends to recognize the coat. If one of the mutations changes the coat, then the immune system won’t recognize it. It’s looking for denim, but there’s only corduroy.”
Dr. Gorski recently participated in a study that took a look at the influenza virus in Wisconsin during the 2009 pandemic, chosen because that year’s strain quickly stopped being very pathogenic (or capable of producing disease). Dr. Gorski and his colleagues asked volunteer blood donors for their consent to test their white blood cells, which are usually discarded after donors give blood (the other components in a donor’s blood – red cells, platelets and plasma – are all able to be transfused into patients).
The next time these study participants donated blood, the lab was sent some of the donor’s white blood cells and leftover serum for processing and storage. Then, if participants experienced flulike symptoms, a nurse was called to take a blood sample and nasal swab for testing. Investigators were interested in learning more about how these participants’ immune responses might cross-protect the general public, and possibly provide the basis for a universal flu vaccine.
The research team’s findings were published in Open Forum Infectious Diseases, Oxford University Press, concluding that “current strain-matched vaccines leave public health gaps due to the long lead time for strain selection, vaccine production and distribution.” Simply put, it takes time to figure out which strains of the flu will be most prevalent each year and should be included in the flu vaccine. A universal vaccine could protect people from these various strains, but investigators aren’t quite there yet.
The more investigators like Dr. Gorski are able to research the influenza virus, the better equipped physicians will be to administer flu vaccines that protect against all strains.
About the expert: Jack Gorski, PhD, is a senior investigator at the Blood Research Institute and associate professor in the Department of Cell Biology, Neurobiology and Anatomy, and the Department of Microbiology and Molecular Genetics at the Medical College of Wisconsin. Learn more about Dr. Gorski.