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A flu expert says the World Health Organization may have been mistaken as to which flu strain is strongest in the northern hemisphere, suggesting that the vaccine is a & # 39; mismatch & # 39; can be and keep people in the US, UK and Canada poorly protected (file)

This year's flu vaccine may not be effective, a top expert warns.

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Dr. Danuta Skowronski, a flu expert from the University of British Columbia told Stat News that this year's flu shot for the northern hemisphere – including the US, UK and Canada – is likely to be a & # 39; mismatch & # 39; is.

Flu shots need to be redeveloped before each season based on scientists' predictions about which species will be most active in the coming months.

World Health Organization (WHO) officials chose the species for the northern hemisphere shot in February and chose the southern hemisphere last week.

For the southern hemisphere, officials chose influenza A / H3N2 and B / Victoria – other than the strains picked for the north, suggesting Dr. Skowronski that the earlier prediction was wrong and the northern shots may not be effective.

A flu expert says the World Health Organization may have been mistaken as to which flu strain is strongest in the northern hemisphere, suggesting that the vaccine is a & # 39; mismatch & # 39; can be and keep people in the US, UK and Canada poorly protected (file)

A flu expert says the World Health Organization may have been mistaken as to which flu strain is strongest in the northern hemisphere, suggesting that the vaccine is a & # 39; mismatch & # 39; can be and keep people in the US, UK and Canada poorly protected (file)

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Every year the flu virus makes its way around the world and usually gets more active in the US in October.

Without failure, between three and five million people worldwide get sick and die somewhere between 290,000 and 650,000 from the disease.

Most people who die are very young, very old or have an underlying condition.

But in the worst flu seasons, healthy people also succumb to the virus.

A child has already died from the flu in the US – an alarming bellwether with which the US may have a particularly bad season.

The 2017-2018 flu season was one of those particularly nasty years for the flu.

More than 80,000 people died of flu in the US that season, including 160 children.

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It was the highest death toll since 1976 and child deaths reached a record of all time, apart from pandemics such as the 1918 Spanish flu, which killed between 20 and 100 million worldwide.

The historically high mortality rate of the 2017-2018 flu season was largely due to the fact that the flu shots that were spread to the US were a bad match for the circulating strains of the virus.

Flu vaccines are the best protection there is against flu – but they are only effective against the strains of the virus on which they are based – and that is a matter of calculated guesswork.

It is impossible to quantify exactly how many flu strains there are. The most common viruses are influenza A and B, but there are others, they vary based on the hosts they attack first (pigs, birds, etc.) and often mutate.

Prior to each season, health officials and flu experts from around the world come together to carefully examine the early cases of flu in each season and the patterns of previous years to predict which species and variations will be dominant that year.

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Flu vaccines are then developed based on a dead form of those viruses or partial viruses.

When scientists' predictions are close, the vaccines are very effective and fewer people die – as long as the vaccination rate remains high. If they are not on the base, diseases rise and the death toll increases.

These predictions are difficult because the strains of the virus vary from continent to continent and the ways in which they move from one to the other vary annually.

But usually the most powerful and common in the north and south are comparable.

The flu season starts earlier in the year in the northern hemisphere, so WHO officials met in February to decide which species should be the basis of the northern shot.

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After limiting the viruses for influenza B / Victoria and A / H3N2, the scientists struggled to make a choice as to which specific variation of the H3N2 virus would pose the greatest threat in the 2019-2020 flu season, Stat reported.

So they went with the type of virus that suddenly got caught in the US at the end of last season.

But Dr. Skowronski thinks that that might have been a mistake.

& # 39; That H3N2 wave was late and evolved the moment they met in February, & # 39; said Skowronski of the tribal selection committee. “And there was a varied mix of H3 viruses. And it was not clear to them, I think (what kind) … would be the clear winner, & she told Stat.

But by the time the officials met again this month to determine the basis for the shot from the southern hemisphere, things had changed.

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In recent years, H3N2 has introduced a challenge for matching shots. It was the same virus that the 2017-2018 recordings offered so little protection – only about 40 percent – against the dominant and particularly aggressive species of that season.

Dr. Skowronski would like to reformulate the shot of the northern hemisphere, based on the shot of the southern hemisphere.

But shortly thereafter, she insists that doctors are prepared that even people who are vaccinated against the flu can go up this year anyway.

In any case, the influenza B virus predicted in February still seems to be the right one, which is especially important because children tend to contract more often and die from B strains.

Last week, World Health Organization officials chose the strains of the virus on which to base the Southern Hemisphere vaccine

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