Americans have been looking forward to herd immunity for almost a year, when enough people are protected by vaccination or infection in the past to stop the spread of COVID-19.
Once there, public officials said masks would not be needed and hugs and handshakes – not to mention gyms, bars and indoor eateries – could return.
But even because more than half of Americans have received at least one dose of vaccine and many others are protected by recent infections, health experts are moving away from the idea of reaching a magic number.
Dr Anthony Fauci, the country’s leading doctor on infectious diseases, no longer wants to talk about herd immunity.
“Instead of concentrating on an evasive number, let’s vaccinate as many people as quickly as possible,” he said during an information session in the White House last week, a sentiment he has since repeated.
What Fauci does not explicitly state, but what others do say, is that with about a quarter of Americans saying they may not want to be vaccinated, herd immunity is simply not an achievable goal.
“It is theoretically possible, but we have rejected it as an association,” said Dr. Gregory Poland, director of the Vaccine Research Group of the Mayo Clinic, said. “At this stage there is no extinction, it is off the table. The only thing we can talk about is control.”
After initially targeting the type of protection the measles vaccine provides, officials are now focused on giving birth similar to the flu: they will acknowledge that there will be frequent outbreaks, but hope to limit it as much as possible.
Americans can go through their entire lives without worrying about measles due to a long-lasting effective vaccine given to more than 90% of children. Although small pockets of infection occur when vaccination rates fall, even people who cannot get the vaccine remain, or they are immunocompromised.
With COVID-19, where vaccines are effective but will not last a lifetime, it does not make it possible to hesitate the vaccine, experts say.
This means that people who cannot be vaccinated or whose immune system is suppressed by medication or disease will remain vulnerable. There will probably always be enough non-vaccinated people to get COVID-19 distributed as soon as it arrives in a community. And even people who are vaccinated will not be 100% protected as a result of such a contagious disease.
But the more people get their shots, the better.
“We need to turn the conversation away from thinking of herd immunity as a target we are reaching or not,” said Lauren Ancel Meyers, a professor of statistics and computer science and director of the COVID-19 model consortium at the University. said. of Texas at Austin. “It’s simple – the more immunity, the better off we will all be.”
The immunity is divided
Herd immunity has been a gripping target as the world has learned more about the emerging SARS-CoV-2 virus over the past year.
Last summer, the World Health Organization set the combined infection and vaccination thresholds to break the distribution chain at 60% to 70%. In December, Fauci set the figure for the U.S. at 75% to 85%. With the advent of highly transferable variants, some have bumped it up to 90%.
However, the reluctance of some Americans to be vaccinated probably put the number out of reach.
“What amazed me most was the incomprehensible rejection of science, even among otherwise intelligent people,” Poland said. “I’m really surprised to see it on a large scale.”
The rift became political. About 79% of self-identified Democrats say they have been vaccinated or plan to do so soon, compared to 46% of Republicans. About 3 out of ten Republicans say according to a poll by the Kaiser Family Foundation, they will definitely not be vaccinated.
This means that America may eventually look like a patchwork quilt, with areas where COVID-19 infections are low and others where the virus continues to thrive.
“There are going to be places, for example in the rural area of Idaho, where you have people with a lot of independent thinking, and that can continue, because you only get up to 25% of the people who are vaccinated,” said Dr. William Schaffner, a professor said. and expert infectious diseases at Vanderbilt University School of Medicine in Nashville, Tennessee.
In Tennessee, Schaffner already sees a ‘striking’ gap between the city and the country. “I’m really worried that this virus is going to smolder in the countryside,” he said.
In areas with low vaccination, COVID-19 will act just like today.
“People who are not vaccinated are just as likely to be infected as ever,” said William Hanage, an epidemiologist at Harvard Chan School of Public Health.
The power of vaccination
The dangers associated with COVID-19 are great. Among unvaccinated people who tested positive for COVID-19, about 20% would have serious illnesses, 5% would end up in intensive care, and between 1% and 2% would die, according to CDC data.
The vaccines will remain susceptible to infection. But also people who are already vulnerable are older than 65, who are oppressed with immunity or have other health problems. Even if they are vaccinated, in order to stay safe, they must take indefinite precautions such as wearing a mask and social distance or risking serious illnesses.
As a result, public health and infectious disease experts are increasingly saying that immunity in the herd should not be the focus. Broad vaccination can turn COVID-19 from a killer into something more beneficial, at least for people who are vaccinated.
Israel, which has the world’s highest vaccination rate so far with 62%, gives a preview of what could happen.
“Once the vaccination rates reached 50%, you saw cases and deaths just drop,” Christina Ramirez, a professor of biostatistics, told UCLA.
Data from Israel show that not only is the vaccine much less likely to become seriously ill or die, but if they get COVID-19, it is almost always a mild case.
“It almost does not matter if the virus is transmitted in the population if it does not cause serious problems,” said Dr. Timothy Brewer, a professor of epidemiology at the University of California, Los Angeles.
The hope is ultimately: the vaccination rate rises high enough so that the pockets of vulnerability shrink and that there are fewer viruses in general.
More people may still decide to be vaccinated as it becomes clear how much protection it offers, said Ajay Sethi, a professor of population studies at the University of Wisconsin-Madison.
“I’m trying to be an optimist,” he said. “I do not want to write off rural areas and say that they will forever be the communities that refuse vaccination. Over time, that will change.”
America’s COVID-19 Future
Another potential wildcard is variants of SARS-CoV-2, the virus that causes COVID-19.
The data from Israel is reassuring for the time being. Even there, where 80% of the circulating virus comes from the more contagious B.1.1.7 variant first detected in the UK, the Pfizer vaccine was very effective. The vaccines Pfizer, Moderna and Johnson & Johnson have been shown to provide some protection against variants.
This can change as new variants emerge, especially if the rest of the world cannot get adequate vaccination. Pharmaceutical companies are already working on new vaccines and enhancers. Both Pfizer and Moderna said people were likely to need annual doses of COVID-19 vaccine last week.
That said, experts like dr. Monica Gandhi, a professor of infectious diseases at the University of California, San Francisco, points to evidence that COVID-19 does not develop the vaccines.
“I’m a little surprised at the pessimism that has been expressed in the press lately about variants and reluctance not to let the vaccines get us through the pandemic. I think that’s the solution,” Gandhi said.
With the spread of the virus, however, things will not recover until November 2019 before the virus has dominated the world, UCLA’s Brewer said.
“Plexiglas barriers in the supermarket will never go away,” he said. “But I think we will come where there is no universal mask.”
For many people, COVID-19 can become a disease in the background, such as flu, waning in winter and summer, requiring a boost every year or every other year.
“It’s quite possible that people who have been vaccinated have a little sniffing in a few years, and it’s actually SARS-CoV-2, but they never know,” Hanage said.
The future of COVID-19 in the US will ultimately depend on the willingness of Americans to accept the vaccines, experts say.
“We’re still going to struggle with low vaccinations for a long time,” said Meyers of the University of Texas. “COVID-19 is such a rogue virus – it spreads quickly and quietly – it will only start to disappear before the vast majority of people are immunized.”
Contact Elizabeth Weise at [email protected]
This article originally appeared in the US TODAY: herd immunity in the US probably impossible, but vaccines can control COVID