Flu Vaccine Effectiveness

Characterized by symptoms such as a high fever, muscle aches, joint pain, headaches, a cough, nasal congestion, nausea, and fatigue, the influenza virus (flu) is one of the more common illnesses we are all susceptible to.  While the virus can make anyone feel miserable for one to two weeks, people with chronic lung diseases, heart disease, diabetes, kidney disease, or obesity, are at a higher risk for developing serious illness, complications, or even death.  The best preventative measure people can take against the virus is to get an annual flu shot.  Studies have shown that vaccination can reduce the risk of contracting the virus, minimize symptoms if the virus is contracted, and reduce the likelihood of complications and death.  Most individuals six months of age and older, are recommended to get an raleigh influenza vaccination every year but some may be wondering about its effectiveness.

Is the Vaccine Effective?

While the strains of seasonal flu vary from year to year, the primary strains for the 2019-2020 flu season are influenza B and influenza A.  Based on research by the US Centers for Disease Control and Prevention (CDC), the 2019-2020 seasonal flu vaccine is estimated to be about 45% effective.  This estimate is based on data collected from patients six months and older suffering from acute respiratory infections in five states including Pennsylvania, Michigan, Wisconsin, Texas, and Washington.  Using respiratory samples taken through oropharyngeal (throat) and nasal swabs, the samples were tested for influenza.

Demographic data from the participants in the study, or their proxies, were collected to determine if they received the flu shot.  Patients that had one or more doses of any seasonal flu vaccine 14 days or more before the onset of illness, were considered vaccinated.  Based on data taken from 4112 adults and children, the vaccine was estimated to be 37% effective against influenza A and roughly 50% effective against influenza B.  The estimates are consistent with historical effectiveness averages ranging between 40%-60%.

Patients that tested positive for the virus, had a vaccination rate of roughly 37% while those that tested negative for influenza, had a vaccination rate of 55%.  This indicates a correlation between those vaccinated and a reduction of flu risk.  In other words, the data suggests the vaccine decreases a person’s risk for contracting the virus.

As historical data has shown, even people that get the flu shot may develop the infection.  However, evidence from the data suggests that those that do get the shot, but still get the virus, have attenuated (reduced or less serious) symptoms, suffer fewer complications, and are less likely to die than those that do not get the flu shot.  While there is not a 100% guarantee that the shot will prevent you from getting the virus, there appears to be substantial public health benefits such as symptom mitigation, reduced hospitalization, and fewer deaths associated with people that receive the vaccine.  The vaccine needs improvement, but the CDC emphasizes that people 6 months and older, should continue to receive the flu shot from their health care providers each year. There is a misconception that the Flu vaccine can “cause the flu” this is not factual. The Flu vaccine can cause some symptoms of mild low grade fever, headache, runny nose and mild congestion. However, these symptoms are very short lived and are certainly not the flu virus. The flu virus can cause extreme illness and even death. Vaccination has proven to greatly reduce this risk.

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