Flu always finds time to spread every year. Despite efforts to encourage the public to get vaccines to prevent infections, the government still expects the disease to affect many Americans.
Darwin Malicdem, writer for Medical Daily says that the flu season usually begins in October. However, the viruses affecting people change from year to year, which makes it difficult to predict how many people and areas are at risk.
The annual virus changes also bring challenges to the Centers for Disease Control and Prevention (CDC) to determine which flu vaccine to use every season. Public health officials review and update vaccines yearly to fight any new virus.
There are four main types of flu viruses, named A, B, C and D. The A and B viruses commonly cause the seasonal epidemics in the U.S.
The C virus causes a mild respiratory illness and does not cause epidemics. The D virus affects cattle and has no known record of human infection.
How Flu Viruses Change
This natural process causes small changes in the genes of an influenza virus. Antigenic drift enables the virus to replicate and produce new ones that are closely related to one another.
This process is the main reason why the CDC and scientists need to update flu vaccines annually. The body’s immune system may not recognize the new viruses, which could lead to the spread of flu.
Antigenic shift affects type A flu viruses. The process leads to major changes that prompt production of new proteins in influenza viruses that infect humans. Majority of the population do not have immunity to the new virus produced through antigenic shift.
Importance of Flu Vaccine
Despite facing different flu viruses every year, the CDC said a vaccine can still be effective to prevent any infection. An individual should get a yearly flu vaccine.
The CDC said the best time to get a vaccine shot is by the end of October, when viruses may start to become more active and spread. However, getting vaccinated later will still provide the same level of protection but getting it earlier may reduce your risk of exposure.
For the 2019-2020 flu season, manufacturers said 162 million to 169 million doses of flu vaccine will be available to the public, according to Staten Island Advance. The CDC said the nasal spray flu vaccine will also be available for the season.