ATLANTA — The flu vaccine turned out to be a big disappointment again.

The vaccine didn’t work against a flu bug that popped up halfway through the past flu season, dragging down overall effectiveness to 29%, the Centers for Disease Control and Prevention reported Thursday.

The flu shot was working well early in the season with effectiveness put at 47% in February. But it was virtually worthless during a second wave driven by a tougher strain, at just 9%.

advertisement

There was “no significant protection” against that strain, said the CDC’s Brendan Flannery.

Flu vaccines are made each year to protect against three or four different kinds of flu virus. The ingredients are based on predictions of what strains will make people sick the following winter.

This season’s shot turned out to be a mismatch against the bug that showed up late.

That pushed down the overall effectiveness to one of the lowest in recent years. Since 2011, the only season with a lower estimate was the winter of 2014-2015, when effectiveness was 19%. A mismatch was also blamed then.

Vaccines against some other infectious diseases are not considered successful unless they are at least 90% effective. But flu is particularly challenging, partly because the virus can so quickly change. Overall, flu vaccine has averaged around 40%.

Flu shots are recommended for virtually all Americans age 6 months or older. Officials say the vaccine is still worthwhile since it works against some strains, and it likely prevented 40,000 to 90,000 hospitalizations over the winter flu season.

The CDC bases vaccine effectiveness on preventing cases bad enough to send someone to the doctor.

— Mike Stobbe

Leave a Comment

Please enter your name.
Please enter a comment.

  • It is not possible to create a vaccine against influenza that would cover each individual strain or mutation. . For 4 years, only 1 time he had the flu . And he had the flu for 3 days. You can make a vaccine out of my blood in a few days. I want to help create a vaccine against influenza from my blood. I agree with you to do, to make and even more so to copy the vaccine or medicine from my blood is very expensive, but during a pandemic, somebody will hardly look at the price.

    Swine Flu or A-H1N1 in Bolivia and Camiri

    Chronology of pandemic swine flu (AH1N1) in Bolivia

    May 31: The first 2 cases in Santa Cruz. Mother (39 years old) and son (7 years old) by plane from New York-USA. Total: 2

    June 1: 1 case in La Paz. An American who rode from Cusco to Peru.

    June 7: 2 cases; 1 in Montero Santa Cruz, a 16-year-old student who returned from Virginia-USA. 1 in Santa Cruz, a young man of 26 years, by land from Argentina. Total: 5

    11 June: WHO World Health Organization announces maximum preparedness for a global pandemic.

    June 15: 4 more cases in Santa Cruz, 2 students from the school of Juan Pablo II and Muirin de Montero. 1 Argentine and 1 Bolivian resident returning from Argentina. Total: 9

    June 18: 1 suspected case in Camiri, a young student who returned from Montero. Currently confirmed cases of the disease in Santa Cruz: 18 Total: 18.

    June 22: 21 cases in Santa Cruz, 3 in La Paz, 3 in Cochabamba, 2 Oruro, 1 Chuquisaca, 1 Tarija. 31 total

    NewsNational
    the flu strain “mutates” at the height of the death season – but the vaccine is still needed, doctors say
    Sarah Swain – 2 hours ago

    Doctors say that some strains have been able to “mutate” since the vaccine was developed this year.
    The municipal flu strain has mutated, which makes the vaccine against influenza potentially ineffective.

    According to experts, this happens in a season of terrible flu, which may worsen.

    The municipal flu strain has mutated, which makes the vaccine against influenza potentially ineffective. (Aap)
    228 people were killed and more than 120,000 Australians were affected by the virus this year.

    A spokeswoman for the World Health Organization, a professor at the Center for the Study of Influenza, a professor at Kanta Subbarao, told News Corp that testing shows that the H3N2 strain – only one of the strains – has mutated.

A roundup of STAT’s top stories of the day in science and medicine

Privacy Policy