U.S. health officials are now planning for all Americans to receive COVID-19 booster shots to shore up their protection while the delta variant is spreading — but not all outside experts agree there’s concrete evidence suggesting that the vaccines’ effectiveness is falling enough to warrant this approach while much of the world waits for vaccines.
The new U.S. plan, as outlined by the director of the Centers for Disease Control and Prevention (CDC) and other top authorities, calls for an extra dose eight months after people get their second shot of the Pfizer or Moderna vaccine.
The doses could begin the week of Sept. 20.
“Our plan is to protect the American people, to stay ahead of this virus,” CDC director Dr. Rochelle Walensky said in a statement.
In their statement, U.S. officials also said it is “very clear” that the vaccines’ protection against infection wanes over time, and now, with the highly contagious delta variant spreading rapidly, there is emerging evidence of reduced protection against mild and moderate disease.
“Based on our latest assessment, the current protection against severe disease, hospitalization and death could diminish in the months ahead,” they said.
Dr. Mark Mulligan of NYU’s Langone Health centre welcomed the announcement as a “proactive” response to signs that vaccine strength is eroding.
“There are hints that this may become an increasing problem given waning immunity mixed with the delta variant,” he said. “Part of leadership is being able to see around the corner and make hard decisions without having all the data. It seems to me that’s what they’re doing here.”
The U.S. is not alone in its new approach. Israel is already offering booster shots to people over 50 to control its delta surge, and European medical regulators said they are talking with vaccine developers about the idea.
While Canada’s national vaccine advisory committee has not made a formal recommendation on boosters yet, Ontario said Tuesday it will soon roll out additional shots for certain vulnerable segments of the population.
WHO, outside experts question plan
But top scientists at the World Health Organization (WHO) bitterly objected to the U.S. plan, noting that many countries are not getting enough doses for their initial rounds of shots.
“We’re planning to hand out extra life jackets to people who already have life jackets, while we’re leaving other people to drown without a single life jacket,” said Dr. Michael Ryan, the WHO’s emergencies chief.
And in contrast to U.S. officials, the organization’s top scientist, Dr. Soumya Swaminathan, said that the data does not indicate that boosters are needed for everyone.
She also warned that leaving billions of people in the developing world unvaccinated could foster the emergence of new variants and result in “even more dire situations.”
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In making the announcement on boosters, the CDC released three studies conducted during the delta surge that suggest that the COVID-19 vaccines remain highly effective at keeping Americans out of the hospital but that their ability to prevent infection is dropping markedly among nursing home patients and others.
However, the new studies — on their own — fall short of the kind of data that some experts thought would be necessary for a recommendation like that.
Some scientists have been looking for signs that hospitalizations or deaths are increasing, as a necessary indicator that boosters might be needed. The new studies, on the contrary, found no change in vaccine effectiveness against hospitalizations.
The studies “would not be sufficient, in and of themselves, to make the case for a booster” to some leading scientists, said Dr. William Schaffner, an infectious-diseases expert at Vanderbilt University.
3 studies shared by CDC
Just last week, U.S. health officials recommended boosters for only some people with weakened immune systems, such as cancer patients and organ transplant recipients. Offering boosters to all Americans would be a major expansion of what is already the biggest vaccination campaign in U.S. history.
Schaffner, who is a liaison to an expert advisory panel that helps the CDC form its vaccination recommendations, said members of the committee were surprised when Biden administration officials this week disclosed plans to call for a booster for the general public.
Of the three studies released by CDC on Wednesday, the one that spoke most directly to a possible need for boosters was a look at reported infections in residents of nearly 15,000 nursing homes and other long-term care facilities.
It found that the effectiveness of the Pfizer and Moderna vaccines against COVID-19 infection dropped, from about 74 per cent in March, April and early May to 53 per cent in June and July.
WATCH | Canadian and American health officials suggest third doses for most vulnerable:
The researchers said it was not clear how much of the decline is attributable to the delta variant and how much might be due to a more general weakening of immunity that could have occurred against any strain.
The study looked at all COVID-19 infections, with or without symptoms. The researchers said more work is needed to determine if there was a higher incidence of infections that resulted in severe illness.
Another one of the studies looked at hospitalizations at 21 hospitals. It found that vaccine effectiveness against COVID-19-associated hospitalization in inoculated people was 86 per cent at two to 12 weeks after second dose, and 85 per cent at 13 to 24 weeks after.
The third study found that protection against hospitalizations stayed steady at about 95 per cent over the nearly three months studied. But vaccine effectiveness against new laboratory-confirmed infections for all adults in New York state declined from about 92 per cent in early May to about 80 per cent in late July.
The researchers said they are not certain why the decline occurred, but they noted it coincided with the delta variant as well as an easing of physical distancing and mask rules.
U.S. struggling to control outbreaks
The call for booster shots is a stark reminder that nearly 20 months into the outbreak, the U.S. is still unable to contain the virus that has killed 620,000 Americans and disrupted nearly every part of daily life.
Just weeks after President Joe Biden declared the country’s “independence” from COVID-19 on July Fourth, emergency rooms in parts of the southern and western states are overloaded again, and cases are now averaging nearly 140,000 per day, quadrupling in just a month.
Health officials said people who received the single-dose Johnson & Johnson vaccine will also probably need extra shots. But they said they are waiting for more data.
The overall plan is subject to a Food and Drug Administration evaluation of the safety and effectiveness of a third dose, U.S. officials said.