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 In theory, that could reduce virus transmission - a goal officials
have been less explicit about - and hasten America's recovery.
“It is not the primary reason (for boosters), but it could actually
be a very positive offshoot," Dr. Anthony Fauci, one of the Biden
Administration's COVID-19 advisers and the nation’s top infectious
disease doctor told Reuters.
The main reason for boosters, Fauci said in a telephone interview,
is to reverse the trend of rising "breakthrough" infections among
people who are fully vaccinated, a point that many experts dispute.
Available data has shown that most severe breakthrough cases have
occurred in people over 65 or among those who are immunocompromised.
That latter group is already recommended for a third dose.
Dr. Larry Corey, a virologist at Seattle's Fred Hutchinson Cancer
Center who is overseeing the U.S.-government backed COVID-19 vaccine
trials, is a proponent of using booster doses to bolster antibody
levels enough to prevent infection.
"If you don't get infected, you're not going to transmit it to
others, and we will more effectively abort the epidemic, and that
has economic benefits," Corey said.
The problem there, many experts point out, is that there is scant
scientific evidence showing that boosters will in fact prevent
infections and transmission.
Some government studies have shown that when infected with the Delta
variant, fully vaccinated people can transmit the virus, mostly to
unvaccinated people.
"If you take a look at the evidence from the United States, it is
very clear that protection against infection and mildly to
moderately symptomatic disease is diminishing," Fauci said.
It is happening among many of the U.S. study populations – including
a recent study
https://www.reuters.com/business/
healthcare-pharmaceuticals/covid-19-vaccines-hold-strong-against-delta-protection-waning-older-adults-2021-09-10
of 600,000 COVID-19 cases in 13 states and large cities. “Not
dramatically, but enough," he said.
'WHAT'S THE GOAL?'
While some 63% of eligible people in the United States are fully
vaccinated, the Delta variant has caused a surge in the deadly
disease among the unvaccinated.
The two most widely used vaccines in the United States – those based
on messenger RNA (mRNA) technology made by Pfizer Inc with BioNTech
SE and Moderna Inc – are highly effective but less so against Delta.
Cases are rising among the vaccinated - including some that result
in hospitalization and death.
The U.S. Food and Drug Administration will release data on a
possible booster shot on Wednesday morning ahead of a Friday meeting
of its vaccine advisory panel. It will include a briefing on the
impact of boosters in Israel
https://www.reuters.com/world/
middle-east/israel-present-covid-19-booster-shot-data-fda-experts-2021-09-05,
where the government has closely tracked recipients of the Pfizer/BioNTech
shot.
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During weekly White House COVID-19 briefings, U.S. Centers for
Disease Control and Prevention (CDC) Director Dr. Rochelle Walensky,
White House COVID-19 Response Coordinator Jeffrey Zients and Fauci
have expressed concern that waning immunity against mild,
symptomatic COVID-19 could lead to reduced protection against severe
disease, hospitalization and death, pointing to data from Israel.
Other countries that have started or are planning booster programs,
including Israel - and in the U.K. for people over 50 - have been
more frank about the goal to reduce transmission.
Debate over booster doses in the United States has become a sore
point for virologists, who largely remain unconvinced that the
vaccines are losing their ability to prevent severe disease and
hospitalization.
This week, an article in the journal Lancet by two departing FDA
vaccine experts and senior scientists at the World Health
Organization, challenged the rationale for booster doses
https://www.reuters.com/world/us/
covid-19-vaccine-boosters-not-widely-needed-top-fda-who-scientists-say-2021-09-13,
saying more evidence is needed to justify their widespread use and
that most cases of COVID-19 are spread by the unvaccinated.
Dr. Paul Offit, an infectious disease expert at the University of
Pennsylvania and a member of the FDA' vaccine advisory panel, is
unconvinced by arguments that boosters are needed just yet.
“The question is, what's the goal? If the goal of the third dose is
to enhance protection against serious illness, there's no evidence
that that's a problem," Offit said. If the goal is to increase
levels of neutralizing antibodies with the aim of decreasing
asymptomatic or mild cases, “then we should see those data.”
Corey said the bar for proving a vaccine prevents disease
transmission is high.
"Is there proof today? No, but there is every reason to believe that
this is possible, and may be beneficial," he said.
Fauci, however, said Israeli data shows that since the booster
campaign started, the country has started seeing a decline in the
virus’ reproduction number, which represents how many other people a
person will COVID-19 is likely to infect. The more immunity in a
population, the lower the reproduction number.
Fauci said he is confounded by arguments from vaccine experts that
boosters are only needed when vaccines stop preventing severe
disease, hospitalization and death.
“What is the magic, mystical issue about hospitalization? I don’t
understand that," he said. "What we’re really saying is we don’t
care about anything except keeping people out of the hospital.
Really? You’re kidding.”
(Reporting by Julie Steenhuysen; Additional reporting by Nandita
Bose in Washingtong; Editing by Caroline Humer and Bill Berkrot)
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