Flu Vaccine Strains May Already Be Off the Mark.
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Topic: Flu Vaccine Strains May Already Be Off the Mark.
Posted By: John L.
Subject: Flu Vaccine Strains May Already Be Off the Mark.
Date Posted: September 30 2019 at 2:55pm
The curse continues, of primitive egg-based manufacturing of most flu vaccine doses. Another strain selected to grow better in eggs so that big pharma can make and sell more flu vaccines. The fact that they may be shooting blanks appears to be of lesser importance.
https://www.scientificamerican.com/article/flu-vaccine-selections-suggest-this-years-shot-may-be-off-the-mark/" rel="nofollow - https://www.scientificamerican.com/article/flu-vaccine-selections-suggest-this-years-shot-may-be-off-the-mark/
Flu Vaccine Selections Suggest This Year’s Shot May Be Off the Mark
The strains chosen for the Southern Hemisphere vaccine suggest the Northern Hemisphere one may not provide optimal protection
By Helen Branswell, STAT on September 30, 2019
Flu Vaccine Selections Suggest This Year's Shot May Be Off the Mark
Credit: Getty Images
It’s never an easy business to predict which flu viruses will make people sick the following winter. And there’s reason to believe two of the four choices made last winter for this upcoming season’s vaccine could be off the mark.
Twice a year influenza experts meet at the World Health Organization to pore over surveillance data provided by countries around the world to try to predict which strains are becoming the most dominant. The Northern Hemisphere strain selection meeting is held in late February; the Southern Hemisphere meeting occurs in late September.
The selections that officials made last week for the next Southern Hemisphere vaccine suggest that two of four viruses in the Northern Hemisphere vaccine that doctors and pharmacies are now pressing people to get may not be optimally protective this winter. Those two are influenza A/H3N2 and the influenza B/Victoria virus.
The strain selection committee concluded the H3N2 and B/Victoria viruses needed to be updated because the ones used in the Northern Hemisphere vaccine didn’t match the strains of those viruses that are now dominant. Influenza epidemiologist Dr. Danuta Skowronski described the significance of those two changes in one word: “mismatch.”
“I think the vaccine strain selections by the WHO committee are obviously important for the Southern Hemisphere but they’re also signals to us because they’re basing their decisions on what they see current predominating on the global level,” said Skowronski, who is with the British Columbia Center for Disease Control in Vancouver.
Flu vaccine is a four-in-one or a three-in-one shot that protects against both influenza A viruses—H3N2 and H1N1—and either both or one of the influenza B viruses, B/Victoria and B/Yamagata. Most flu vaccine is made with killed viruses, and most vaccine used in the United States is quadrivalent—four-in-one.
There was great uncertainty around which version of H3N2 to choose for the Northern Hemisphere vaccine when the committee met last February—there was a lot of variation between the strain the U.S. was seeing and the H3N2 viruses sickening people in Canada and Europe. There was so much uncertainty, in fact, that the committee delayed making the choice of the H3N2 strain for a month to try to get a clearer picture.
In the end, the committee selected a version of the virus that was causing a wave of late season illness in the United States. (Canada also had a late season surge of H3N2 activity, but caused by a different version of the virus.)
“That H3N2 wave was late and it was evolving at the time that they met in February,” Skowronski said of the strain selection committee. “And there was a diverse mix of H3 viruses. And it wasn’t clear to them, I guess, [which strain] … would emerge the clear winner.”
It appears the virus that was ultimately selected is not the H3N2 that dominated during the Southern Hemisphere’s winter 2019 season.
Scott Hensley, an associate professor of microbiology at the University of Pennsylvania, said the variant of H3N2 viruses that just swept through the Southern Hemisphere is more likely to be the main cause of H3N2 infections for the Northern Hemisphere this winter than was the case in the U.S. late last winter and into the early spring.
But that version of H3N2 is difficult to grow in eggs, which is the way the vast majority of flu vaccines is made, he noted, suggesting that fact may have influenced the thinking
In recent years the H3N2 component has generally been the least effective part of the vaccine. If H3N2 viruses predominate this coming flu season, a vaccine mismatch could add to the severity of the season. But if those viruses play a smaller role this winter, the impact of a mismatch will be less significant, making it hard to predict if this choice is going to turn out to be a problem.
Flu circulation “remains difficult to predict and flu viruses are constantly breaking rules that we try to establish for them,” Hensley said, adding that flu vaccines “often protect against severe disease even when … mismatched.”
The selection of a new B/Victoria virus for the Southern Hemisphere 2020 shot also concerns Skowronski. There was almost no influenza B activity in the 2018-2019 flu season and it’s been several years since B/Victoria viruses have caused much illness. As a result, there may not be a lot of immunity to those viruses in the population, she said.
B/Victoria flu viruses are especially hard on children, Skowronski said.
Given the possibility that a couple of the components of the vaccine might not be well-matched to circulating flu viruses, Skowronski said it will be important for doctors to realize vaccinated patients may still contract influenza. For those who are at high risk of developing severe illness, rapid treatment with flu antiviral drugs should be considered.
She also suggested older people or people who have underlying health problems—in other words, those who are likely to develop a severe case of flu if they contract the virus—should take steps to avoid being around sick people.
The sliver of good news: The officials meeting at the WHO last week concluded that the H1N1 and the flu B/Yamagata components of the Southern Hemisphere vaccine didn’t need to change, suggesting they are representative of the strains of those viruses we’re likely to encounter this winter.
Republished with permission from STAT. This article originally appeared on September 30, 2019
ABOUT THE AUTHOR(S)
Helen Branswell
Helen Branswell is STAT's infectious diseases and public health reporter. She comes from the Canadian Press, where she was the medical reporter for the past 15 years. Helen cut her infectious diseases teeth during Toronto's SARS outbreak in 2003 and spent the summer of 2004 embedded at the US Centers for Disease Control and Prevention. In 2010-11 she was a Nieman Global Health Fellow at Harvard, where she focused on polio eradication. Warning: Helen asks lots of questions.
Credit: Nick Higgins
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Replies:
Posted By: Guests
Date Posted: September 30 2019 at 4:26pm
Yep read this too. My theory...something is better than nothing.
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Posted By: Technophobe
Date Posted: December 03 2019 at 1:15pm
Technophobe: I can't speak for America, but we do usually have flu strains in common. This seems to be good news for this year.
Experts say a life-threatening flu virus is on its way to the UK - here’s what to look out for
By Lloyd Bent
Friday, 1st November 2019, 10:56 am
Updated
Friday, 1st November 2019, 10:57 am
A life-threatening flu epidemic could hit the UK this winter, experts have warned.
Health officials confirmed two cases in the US where flu has caused deaths, including a four year old boy in California who died last month, and another child of the same age who died in New York this week.
It has been warned that these cases could indicate a severe outbreak of the virus, which is usually common between October and March.
When is flu season in the UK?
Britain’s flu season tends to mirror that of Australia, which has seen a number of deadly cases take hold in recent months.
So far there have been fatal 662 cases of flu recorded in Australia this year, where it is believed that three strains of the virus are in circulation.
Professor Robert Dingwall, a public health expert at Nottingham Trent University, told The Sun Online, "The Australians have had a very bad flu season and we should expect the same flu strain to appear here later this winter.”
However, he did say that since the strain of the virus is one that was present in the UK last year, vaccines will be readily available.
He advised anybody who has not been vaccinated should do so as soon as possible, and that it is highly important for people who are in vulnerable groups who are offered the vaccine.
He added, "This is especially the case if you are working in a job that involves a lot of contact with the general public, especially with children - toddlers are particularly good at spreading the virus."
What are the symptoms of flu?
According to the NHS, symptoms of flu are:- a sudden fever – a temperature of 38C or above- an aching body- feeling tired or exhausted- a dry cough- a sore throat- a headache- difficulty sleeping- loss of appetite- diarrhoea or tummy pain- feeling sick and being sick
Source: https://www.thesouthernreporter.co.uk/news/read-this/experts-say-life-threatening-flu-virus-its-way-uk-heres-what-look-out-824627" rel="nofollow - https://www.thesouthernreporter.co.uk/news/read-this/experts-say-life-threatening-flu-virus-its-way-uk-heres-what-look-out-824627
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