Archive for the ‘vaccines – immunization’ Category

How effective are vaccines?

September 9, 2020

Answer: Not as much as you might expect.

Excerpted from a September 2019 White House report which looked specifically at flu and coronavirus vaccines ….

There is considerable variation from year to year in how much the flu vaccine reduces the risk of contracting the seasonal flu and flu-related illnesses.

Over the past 14 years, influenza vaccine effectiveness has ranged between 10% and 60%.


Much of the variability depends on which viral strains predominate in a given year and, more specifically, whether the vaccine matches the viral strain that is circulating in a given flu season.

Although a mismatch between the vaccine and the virus circulating during a flu season reduces efficacy, vaccines still provide some protection against flu illness and decrease the severity of the illness, due to immunologic similarity between the viruses.


When it comes to pandemic viruses