There are viruses that are mutating, and this is very evident in the case of the SARS-Cov-2 virus which has been undergoing repetitive mutations and different strains are being reported periodically.
Flu Vaccines Do Not Match The Main Circulating Virus Strain
Now even the flu virus has also been found to have changed. The biggest concern is that the present flu vaccine may not be as effective against the new strain. Influenza vaccines protect against the H3N2, H1N1, and 2 strains of Influenza B.
This may be true as a strain of influenza was found to have infected a large number of people in Michigan followed by Wisconsin in the United States during November 2021 and that most of the infected people had already been vaccinated.
Professor Scott Hensley, a professor of microbiology at the University of Pennsylvania has been at the forefront in the study of the strains of influenza. He has noted that the present version of the H3N2 virus has been particularly significant and the vaccine has not been effective against it. This strain has been found to evade the antibodies that the human body generates as a stimulus.
The Centre for Disease Control and Prevention (CDC) in the United States has been tracking the trend of infections of influenza and was concerned with the comeback of influenza along with Covid -19. Immunization against influenza had taken a back seat as Covid-19 had dominated world medical attention.
The need of the hour is to research and produce more effective vaccines against the H3N2 and the 2a2 strains. Vaccine-making methods need to evolve from the older method of incubating chicken eggs over several weeks.
There is also a positive flip side. The changes in the influenza viruses have not been found to affect the T cells which are the next line of defense in the immune system of the body. This means that though the existing vaccine is not strong enough to prevent infections, it can help provide some protection against severe hospitalization and death.
Health experts also believe that the protocols of wearing masks, social distancing, and decrease in tourism and international travel helped curb the larger scale spread of influenza.
The CDC believes that the influenza virus can mutate, evolve and develop different strains by the time the Covid-19 pandemic diminishes, and if the seasonal vaccines are not matched with the strains circulating at that time, the efficacy of vaccines can go down below 10%.
Professor Hensley remembers this evolution of the H3N2 strain that had occurred during 2014-2015 and had similarly rendered the existing seasonal vaccine partially ineffective. Even during 2019-2020, the seasonal vaccines had only 39% effectiveness against the strains of the flu virus. In fact, an examination of the past 16 flu seasons report on a CDC chart shows that vaccines have had fluctuating effectiveness varying from 10% to 60%.
Researchers have mentioned that while the H3N2 and 2a2 strains are predominant at present and are causing rising infections both in the United States and the rest of the world, it is possible other variants of H3N2 could come up in the future.
Influenza is a serious disease and CDC records reveal that this disease causes as many as 700, 000 hospitalizations in a year and 12,000 to 52,000 people in the United State succumb to the deceptively mild flu.
A professor of infectious diseases at the University of California recommends a flu test even if one has tested negative for Covid-19.
The need of the hour is to continue research into the different strains of influenza and find a strong effective vaccine.
