- Dr. Fauci is disseminating some of the first evidence that vaccines can help prevent the spread of COVID-19.
- The hunch depends on 2 new studies, which suggest that vaccinated people do not transmit the coronavirus well, even if they get sick.
- Being vaccinated, said Fauci, “is not only good for you,” but it can also protect others.
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Dr. Anthony Fauci says there is new evidence that a COVID-19 vaccine can not only protect people who get it, but also other people they come into contact with.
“Some studies are pointing in a very favorable direction,” said Fauci, director of the National Institute of Allergy and Infectious Diseases, on Wednesday during a COVID-19 meeting at the White House.
Although he warned that more conclusive research is still needed, the doctor pointed out two studies, launched this month.
Together, they are some of the first evidence we have that even if vaccinated people become ill with COVID-19 – in what is called a “discovered” infection – the chances of transmitting their disease to others are much less than if they remained unvaccinated.
The number one “imminent issue,” said Fauci, is: “does the vaccine prevent transmission?”
These two studies are the first signs that point to a “yes”.
Not everyone who receives COVID-19 transmits it, whether vaccinated or not
A healthcare professional administers a dose of the Pfizer-BioNtech COVID-19 vaccine to a pregnant woman at Clalit Health Services in Tel Aviv on January 23, 2021.
Jack Guez / AFP via Getty Images
The first evidence, a peer-reviewed study published in The Lancet earlier this month, suggests that people who are infected with COVID-19, but who have lower viral loads on the back of their nose and throat, are much less likely to infect others, spreading their diseases.
In the study, conducted in Spain during March and April 2020, scientists measured the amount of viruses that 314 patients with different coronaviruses had during their infections, rubbing their nose (nasopharynx) and measuring their viral loads.
Then they watched which of these patients passed their coronavirus to someone else.
They found that the higher a patient’s viral load, the more likely they were to transmit their disease to someone they came into contact with. In addition, the higher the spreader’s viral load, the faster the infected person tends to become ill.
“In other words, higher viral load, good transmissibility, low viral load, very poor transmissibility,” said Fauci.
Until now, it was unclear whether viral load affected infectiousness, so there was some concern that even people with low levels of viruses could spread their illnesses well.
It is important to note, however, that this study was carried out almost a year ago, when there was still not so much concern about the rapidly spreading variants, so it is difficult to interpret what it means for viral load and infectivity now.
Vaccinated people seem to have less virus to spread, even if they get sick
Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, is preparing to receive his first dose of a COVID-19 vaccine at the National Institutes of Health on December 22, 2020 in Bethesda, Maryland.
Patrick Semansky-Pool / Getty Images
The second study, which came out last week and has not yet been peer-reviewed, suggested that people who were vaccinated in Israel “significantly reduced” viral loads when and if they became ill, starting at least 12 days after full vaccination.
Together, these two studies suggest that:
- vaccinated people tend to have lower viral loads, and
- lower viral loads are linked to less viral spread
It is possible, then, that the vaccination of a large number of people may help to crush the coronavirus outbreak, not only by keeping the vaccinated individuals healthy, alive and out of the hospital, but also by avoiding any of the vaccinated people who may eventually become ill ( asymptomatic) to transmit his disease to others.
“It is yet another example of the scientific data that is beginning to point to the fact that the vaccine is important, not only for the health of the individual, to protect him from infections and diseases,” said Fauci, “but it also has very important implications of a public health posture for interfering and reducing the dynamics of the outbreak ”.
Further studies on viral loads in vaccinated people will need to be completed and validated by independent scientists in other countries around the world, to see if this trend really continues globally (Moderna and Pfizer already have such studies underway, Fauci said).
But in Israel, which has reached the leadership of the global group with almost 30% of Israelis now fully vaccinated, there is positive evidence. Another new study by Israel’s largest health provider this week suggests that among people who were vaccinated with Pfizer’s mRNA injections, there was a 94% drop in symptomatic COVID-19 cases when compared to unvaccinated peers.
Being vaccinated “is not only good for you, your family and your community,” said Fauci. “This will have a very important impact on the dynamics of the outbreak in our country.”