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Flu’s return will shape the coming months of pandemic
public health

Flu’s return will shape the coming months of pandemic

3 min. 01.10.2021
French government's adviser says flu immunity may have diminished after two winters with few cases
Photo credit: Shutterstock

Charting the course of the pandemic during the coming months is likely to involve a more traditional winter nuisance: the flu.

As countries from Italy to Canada lift restrictions, travel resumes and colder temperatures set in, influenza will probably start circulating as well. That’s after measures to thwart Covid-19 such as masks and ventilation kept the flu at bay for the past year and a half. 

Efforts have already been under way to lessen the potential strain on health systems dealing with both illnesses. A U.K. study released late Thursday showed that it’s safe for people to get Covid and flu shots at the same time, which might help increase vaccine uptake and cut down on appointments as the country rolls out booster doses. 

“This is a real concern for policy makers,” Neil Ferguson, the Imperial College epidemiologist whose models are used by the U.K. government, said at a conference in Paris. “It’s highly likely we will continue to see circulation of reasonably high levels of Covid through the winter, and having seasonal flu on top could pose again significant additional burdens on health systems.”

Ferguson and others at the meeting said vaccination in rich countries means there probably won’t be a surge in deaths from the coronavirus, but that waning protection from those shots and other factors could still mean plenty of people end up in the hospital. Meanwhile, flu immunity may also have diminished among the general population after two winters with few cases, according to Arnaud Fontanet, an epidemiologist who advises the French government. 

Concern about withering Covid protection prompted Israel -- one of the first countries to start vaccinating early in the year -- to begin administering booster shots months ago. 

“It was pretty striking for us to see early on that a majority of our severe cases were among fully vaccinated individuals,” said Ran Balicer of Israel’s Clalit Research Institute. 

Britain began offering boosters to people age 50 and over and other vulnerable groups last month. Giving flu shots at the same appointment would make it easier for both patients and the health service, said Rajeka Lazarus, a consultant in infectious diseases and microbiology and chief investigator for the U.K. report released on Thursday. 

The study -- involving researchers at the University of Bristol, and University Hospitals Bristol and Weston NHS Foundation Trust -- showed that side effects from getting the vaccines at the same time were mild to moderate, with no negative impact on the immune response to either shot. 

It involved 679 adult volunteers at National Health Service sites in England and Wales who were due for their second dose of either the Pfizer Inc.-BioNTech SE or AstraZeneca Inc. vaccines. They were divided at random into two groups to blindly receive different combinations of shots or a placebo in opposite arms over two visits between April and June. The results haven’t yet been peer-reviewed. 

Results from the British study provide a strong indication that people can safely receive their booster doses with a flu shot, according to Lazarus. 

Ferguson presented data at the Paris conference showing that the shot from AstraZeneca and its partner, the University of Oxford, protected less than Pfizer-BioNTech’s against the delta variant. Like Israel, he said the U.K. had seen “clear evidence of waning protection” from both shots against mild disease as well as more severe outcomes. 

After two doses, the Astra shot offers 52% protection against mild symptomatic disease caused by delta, compared with 90% for the Pfizer one, according to Ferguson’s data. 

Delta may have turned SARS-CoV-2 into “one of the most transmissible respiratory viruses we have ever seen,” with a reproduction rate between 6 and 9, he said.

©2021 Bloomberg L.P.


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