By Kim Mackrael 

Several countries have shifted their guidance in recent days on who should receive the AstraZeneca PLC vaccine, as public-health officials continue to weigh the risk of the vaccine against the prevalence of Covid-19 cases.

The AstraZeneca shot hasn't been cleared for use in the U.S., unlike Covid-19 vaccines from Pfizer Inc., Moderna Inc. and Johnson & Johnson. But in some wealthy countries where the supply of those vaccines has been more constrained, AstraZeneca doses have been offered to people as young as 30, showing the wide variation even among wealthy countries in vaccination campaigns.

On Friday, the U.K.'s vaccines advisory body said the vaccine produced by AstraZeneca, which has raised concerns among health experts due its possible link to rare blood clots, should preferably not be given to people under 40. Previous guidance suggested the vaccine should preferably not be given to people under 30.

In Canada last week, members of a national expert panel referred to the vaccines made by Pfizer-BioNTech and Moderna as the preferred option after elected officials had earlier encouraged citizens to get the first vaccine available, which for some age groups was AstraZeneca's shot.

Meanwhile, German officials on Thursday took the opposite tack, saying they would make the vaccine available to all adults after earlier limiting it to those 60 years and older, as it sought to speed up a vaccination campaign that had gotten off to a slow start.

AstraZeneca has struggled to pull together the data required for an emergency-use authorization for its Covid-19 vaccine in the U.S., and on Friday people familiar with the matter said it could skip that step in favor of pursuing a more time-intensive application for a full-fledged license to sell the shot. U.S. government and public-health officials have said they have ample supplies of other vaccines that are already authorized for use.

Health officials point out that with the pandemic abating in certain countries, the calculations around the benefits of receiving a vaccine change.

British officials said Friday that while the risks of suffering the rare blood clots from the AstraZeneca vaccine are minuscule, they now outweigh the risks of someone under 40 suffering a fatal Covid-19 case. The calculation of the overall safety of the vaccine itself hasn't altered, the U.K. medicines regulator said.

They said unvaccinated individuals under 40 should receive alternative vaccines, "where available and only if this does not cause substantial delays in being vaccinated."

Raywat Deonandan, an epidemiologist at the University of Ottawa, said it is reasonable for experts' advice to change as new evidence emerges, and officials should be open with the public about what they know and recommend.

But he said officials can struggle to communicate both the risks and benefits of the AstraZeneca vaccine, adding to confusion and potentially chipping away at public trust.

He said confusing messaging has been displayed in Canada: Last month authorities in many parts of the country began allowing people in their 40s and early 50s to book appointments for AstraZeneca's vaccine. Prime Minister Justin Trudeau, who has repeatedly said the best vaccine is the first one that is available, was among those who signed up.

Yet on the day Mr. Trudeau received his shot, the expert panel, called the National Advisory Committee on Immunization, said it preferentially recommended the messenger RNA vaccines produced by Pfizer-BioNTech and Moderna. It said AstraZeneca's vaccine should be offered to those 30 years and older who don't want to wait, and for whom the benefits outweigh the risks.

The panel last week said individuals needed to be aware of their options so they could make an informed choice about whether to be vaccinated with the first available vaccine, or to wait for a messenger RNA option.

"The only message that really got through [in past weeks] was, 'accept the first vaccine that's offered to you,' " said Prof. Deonandan. "Now you hear it's OK to wait for the better dose? That's a slap in the face."

Canada's chief public health officer, Theresa Tam, said she didn't see the advice from the government and the panel as different.

"Everyone is trying to provide the best information in order for everyone to make a decision," Dr. Tam said.

Michelle Baysan, who tweeted about getting her vaccine last month, said she was bothered by the change in tone.

"Now I have anxiety that I've injected something into myself that 'isn't the best option,' " said the 43-year-old from Richmond, British Columbia. Still, she added that she was glad to have received a vaccine dose.

The Canadian advisory panel has said the risk of vaccine-induced immune thrombotic thrombocytopenia, or blood clotting, was about one in 100,000. As of May 6, Canada had reported 11 cases of blood clots and three blood clot-related deaths. It had administered more than 2 million AstraZeneca shots as of May 1.

In the U.K. as of April 28, there were 242 reported cases of blood clots in people receiving the AstraZeneca vaccine. They resulted in 49 deaths. So far 22.6 million first doses of the AstraZeneca vaccine have been administered in Britain.

Britons aren't usually given a choice of which vaccine they receive, unless they are in a younger age group, with doses allocated on the basis of what is available and can be easily stored and administered. Opinion polling and data on take-up of vaccines suggest concerns around blood clots haven't significantly dented Britons' willingness to get vaccinated.

Other countries have seen more hesitancy. In Australia, where the AstraZeneca vaccine is recommended for those 50 years and older, a poll by Essential Research found 37% of all adults said they would be willing to get either the AstraZeneca or Pfizer vaccine, while 27% said they would only be willing to have the Pfizer shot. Just 3% of those surveyed said they would take AstraZeneca's vaccine but not Pfizer's, and 14% said they wouldn't want to take either vaccine.

In Europe, just over a third of Germans and 23% of French people said they considered the AstraZeneca vaccine to be safe, according to a recent survey from YouGov.

Meanwhile, health officials in the U.S. have said a 10-day halt in administering Johnson & Johnson's Covid-19 vaccine, which has also been associated with rare blood clots, have made some Americans more hesitant to get vaccinated.

Canadians' confidence in the AstraZeneca vaccine rose sharply during the second half of April, a poll from the Angus Reid Institute suggested, corresponding with the period when many members of Canada's Generation X, or those born between 1965 and 1980, signed up for appointments. Doses of that vaccine were previously set aside for people over 55 in most provinces, but uptake had slowed, experts said, prompting a gradual expansion to younger age groups.

Gen Xers were posting selfies of their inoculations and encouraging others to get the shots. A survey conducted between April 20 to 22 found that 52% of Canadians who were willing to be vaccinated were comfortable getting AstraZeneca's vaccine, up from 41% earlier in the month.

Heather Badenoch, a 45-year-old Ottawa resident who spent three days trying to snag an AstraZeneca appointment at overbooked pharmacies, said she was glad to have some protection, especially because her husband and mother-in-law would both be considered high risk if they contracted Covid-19.

"Zero regrets and pleased to have the antibodies," Ms. Badenoch said last week.

Jason Douglas and Max Colchester contributed to this article.

Write to Kim Mackrael at kim.mackrael@wsj.com

 

(END) Dow Jones Newswires

May 09, 2021 14:11 ET (18:11 GMT)

Copyright (c) 2021 Dow Jones & Company, Inc.