Universal or selective boosters: Who should get a third dose of the COVID-19 vaccine?
Universal or selective boosters: Who should get a third dose of the COVID-19 vaccine?
The scientific community does not agree on booster doses in developed countries, while some
nations have failed to vaccinate even half of their population.
By: Jenny Manrique
Administering third shots of the COVID-19 vaccine has become a hotly-debated issue in recent
weeks. The White House plan for the boosters to reach the entire population contradicts the
guidelines of the Centers for Disease Control (CDC), which have advocated a tiered approach,
prioritizing immunocompromised people and high-risk workers. Some developing countries do
not have enough vaccines to reach even half of their population, while the United States and
other rich nations have stored up five doses of the vaccine for each inhabitant.
Currently, only those who took the first two doses of the Pfizer vaccine are eligible for a third
one. Boosters are not yet available for people who received the Moderna and Johnson &
Johnson vaccines. Two scientists, who also differ on who should receive the third doses and
when, explained their reasons at a briefing hosted by Ethnic Media Services.
“Based on the raw data, I would say that universal boosting, and possibly three or four doses,
would be very beneficial in slowing the spread of the COVID-19 virus and bringing its end
faster,” said Ben Newman, Chief virologist at the Global Health Research Complex at
Texas A&M University.
According to Newman, data from the Food and Drug Administration (FDA) suggest that “no one
is fully vaccinated,” and that what we currently have is evidence of waning immunity. “As time
passes after vaccination, the amount of protection decreases to around 50% … After five
months, the amount of protection against death remains constant at around 90%, but the virus
has got faster and better at reproducing very consistently throughout the outbreak.”
The contagious Delta variant and its 11 mutations are now responsible for 99% of cases. The
effectiveness of vaccines against Delta is almost the same as against other variants, although it
decreases between 5% and 10% among people over 65.
“The benefit of a booster is very large regardless of age group,” Newman continued. “With a
booster after the second vaccine, people end up with as much as 50 times more antibodies, so
the benefits appear to be universal.”
For the virologist, public health policy should focus on ending the coronavirus through
vaccination, since its fatality rate is 2%. In other words, one in 50 people who contract
COVID-19 is likely to die. Although viruses such as polio and smallpox were eliminated with
vaccines after many years of circulation and diversification among humans, COVID can be a
greater challenge due to its mutational capacity which “will eventually be a problem much more
difficult to solve than it is now.”
Global equity
Other scientists argue instead that the Coronavirus is endemic and impossible to eradicate. Dr.
Monica Gandhi, Professor of Medicine at the UC San Francisco’s School of Medicine, explained
that reducing COVID from an epidemic to an endemic, to make it manageable without
burdening hospitals or other medical resources, “is what will allow a complete return to
normality.”
Gandhi explained that SARS-CoV-2 is impossible to eradicate due to the inherent properties of
the pathogen: having reservoirs in animals, a high level of transmissibility, symptoms
overlapping with other respiratory diseases, and a long period of infection, which spreads
between asymptomatic and symptomatic carriers.
Although the antibodies generated by vaccines are naturally going to come down with time, they
“allow the rise of T cells and B cells which go into your memory, and fight viruses in a very
durable way,” Gandhi said. These cells produce high levels of neutralizing antibodies and
modulate protection against the severity of the disease and all variants of the virus.
According to CDC data, 183 million Americans are fully vaccinated, with 4,000 deaths among
them. Among the deceased, 86% were over 65, a number that according to Gandhi shows that
although the effectiveness of the vaccine is not 100%, and someone can contract a
symptomatic infection after inoculation, “cases are very rare both in terms of hospitalizations
and deaths.”
So, who needs an additional booster? Gandhi is in favor of the “selective booster strategy” in
which “definitely” immunocompromised patients, those over 65, and health workers highly
exposed to the virus, are prioritized for receiving third doses.
“We want to prevent Americans from getting a cold, but we let vulnerable and healthcare
workers die in the rest of the world, so I have a really hard time distinguishing the booster
discussion from the global vaccine equity discussion,” Gandhi said.
For the doctor it is “impossible to escape the responsibilities of rich countries who have most of
the vaccine supply.” Out of 6 billion doses administered in the world, only 2.2% have been given
to low-income countries, while rich nations such as the United States, have stored up five doses
for every inhabitant.
In this regard, Newman of Texas A&M says that “it is real” that each additional dose in the US is
potentially one less dose in another part of the world, but he considers that COVID should be
fought like a fire: start by putting it out completely in one place, then expand the rim.
