How effective was the 2015-16 flu vaccine? To quote Dr. Danuta Skowronski of the BC Centre for Disease Control, “It’s an improvement over the previous year, because it couldn’t be worse, frankly”.
The vaccine was less than 45 to 50 percent effective in protecting against the flu. The 2014-15 flu shot offered virtually no protection because the wrong strain of virus was put in it.
In the past, experts thought that the flu vaccine was between 70 and 90 percent effective. That turned out not to be true because data used to come up with those figures was industry funded and inaccurate.
A new testing method is currently used to determine how effective the flu shot is each year. It’s called the test negative design (TND) and was first used in Canada in 2004. The system tests people who turn up with flu like symptoms at hundreds of doctors’ offices in Canada. Doctors take a sample from every patient, which is sent off for lab testing. A record is made of whether the person got the flu shot or not. This is a much more reliable testing method and it’s showing how truly ineffective the flu shot is in most instances.
Another interesting finding was that the more often a person receives the flu vaccine, the less effective it tends to be. So people who get a flu shot every year are worse off than those who’ve never had it or receive it irregularly. This is a very inconvenient fact for vaccine manufacturers. Most doctors still recommend everyone receives the flu shot every year, and in particular vulnerable groups such as the elderly or immune compromised individuals.
Another interesting fact is that those people are more likely to mount an inadequate immune response to the vaccine; that is their weakened immune system does not generate sufficient antibodies and thus the vaccine is ineffective.