As coronavirus cases plummet across the country and vaccinations total 1.7 million Americans a day and rising, health experts are increasingly adopting a new tone in their pandemic assessments: optimism.
“I may be wrong, but I don’t think we’re going to see a fourth big increase,” said Dr. Paul Offit, a vaccine specialist at Children’s Hospital of Philadelphia. “I think we’ve seen the worst.”
Many epidemiologists and other scientists, while still cautious, say they feel increasingly hopeful that the rest of 2021 will not repeat last night’s nightmare.
The arrival of spring is likely to help the coronavirus cases plummet as the warmer climate allows people to spend more time outdoors and creates a less hospitable environment for the virus, experts say.
But the biggest factor, paradoxically, is something that the country spent last year trying to avoid.
While 12% of Americans received at least one dose of the COVID-19 vaccine (almost 20% from Alaska), many more people – approximately 35% of the country’s population – have already been infected with the coronavirus, Offit estimated. Studies have found that people who survive COVID-19 have immunity for several months, although it is likely to last even longer.
University of California, San Francisco epidemiologist Dr. George Rutherford said one of the reasons why cases are falling so quickly in California “is because of naturally acquired immunity, especially in southern California.” He estimated that 50% of Los Angeles County residents were infected with the virus at some point.
“We are actually talking about something that is starting to sound and sound like collective immunity – although true collective immunity is a long way off in the future,” said Rutherford recently.
Herd immunity is achieved when so many people have immunity that a virus cannot find new hosts and stops spreading, resulting in protection for the entire community. Scientists believe that, in the case of coronavirus, the limit can reach 90%. The United States has not reached that limit, but every step towards it slows down transmission, experts say.
The effects may be greatest in places that have suffered the worst outbreaks of COVID-19. After a terrible wave of autumn and winter that killed more than 12,000 people, it is estimated that 33% to 55% of county residents have already been infected with the coronavirus, according to the researchers.
These previous infections have attenuated coronavirus transmission so significantly that they have changed the current outbreak trajectory in LA County, where new daily cases have been falling for five weeks, said Dr. Roger Lewis, director of hospital demand modeling COVID-19 to the County Department of Health Services.
“If you had exactly the same behavior and type of virus circulating as we do now, but we were at the start of the pandemic and no one was immune yet … we would be in the middle of a continuous wave,” he said. “The fact that cases are now decreasing, rather than increasing, is because approximately one-third of everyone in Los Angeles County is immune to COVID.”
But experts warn that the battle has not yet been won.
New variants of the coronavirus can undermine these projections, either by being more resistant to existing vaccines or by finding a way to spread more easily. Changes in behavior can also make this good news debatable, as it is only valid if people follow the care they have been taking so far, experts say.
“I don’t want to give a false sense of security here,” said LA County Chief Science Officer Dr. Paul Simon, who pointed out that 60% of Angelenos’ inhabitants would remain vulnerable even if more than a third had already been infected. with coronavirus. “Unless they have been vaccinated, they remain susceptible. I think we need to remain vigilant. “
Across the country, coronavirus cases have dropped to levels not seen since late October, according to federal officials.
Since the beginning of the pandemic, nearly 30 million Americans have tested positive for the coronavirus, but the actual number of people who contracted the virus is probably three or four times higher due to low levels of testing and the fact that many infected people never develop symptoms, Experts say.
The large number of infections has a high cost. The death toll in the country is approaching 500,000, far greater than any country in the world, and even more have survived, but continue to suffer the persistent effects of their illnesses, some of them serious. Allowing COVID-19 to run rampant to quickly achieve collective immunity, as some had promoted in the beginning of the pandemic, would have led to even more deaths and chronic health problems, experts say.
It is not yet clear exactly what the limit is for collective immunity with this virus, with some scientists estimating that collective immunity can be achieved when 50% of people are immune, while others believe the limit is closer to 90%, said Simon , from LA County. The uneven geographical distribution of infections can also leave some pockets of the county more vulnerable than others, he said.
“We do not yet know what level of vaccination and protection it would take to obtain collective immunity across the county,” Simon said at a news conference on Friday. “As we see the number of new cases drop dramatically – I think this will be the best clue that we are achieving collective immunity, especially if we see it across the county.”
The biggest obstacle to ending the pandemic is the proliferation of coronavirus variants,
especially if they are more transmissible or less susceptible to vaccines. For example, variant B.1.1.7 that emerged in the UK is about 50% more contagious than its predecessors and could fuel outbreaks in places where large groups of people remain vulnerable to disease.
Dr. Peter Hotez, dean of the National School of Tropical Medicine at Baylor College of Medicine, said he thinks flying to visit friends and family will be normal and safe in August. But, because of the variants, he cautioned people to “be careful with the marchers.”
“This is, I think, the biggest crisis we face now in our pandemic COVID-19,” he said in a recent interview with American Medical Assn. “As bad as 2020 was, we are now looking at version 2.0 of this pandemic from the variants.”
But others are more optimistic. Offit said he would be concerned if people who have had COVID-19 or been vaccinated were being hospitalized for infections caused by a new variant.
“This line has not been crossed,” he said. “You just want to keep people out of the hospital and it seems that so far there is no variant that has escaped immunity induced by a disease or vaccine.”
At a COVID seminar at the UCSF Department of Medicine last week, Dr. Monica Gandhi, an infectious disease specialist, put it simply: “Try not to worry about the variants.”
Offit said he remains hopeful about the country’s trajectory during the summer and as more people are vaccinated. “What worries me a little bit is when you get to September and then it gets colder again, and there may be a variant that appears,” and people stop wearing masks and physically distance themselves, said Offit.
Dr. Rochelle Walensky, director of the Centers for Disease Control and Prevention in the United States, cautioned against seeing decreasing trends in cases as a reason to lessen masking and other safety precautions.
In an interview with the Journal of the American Medical Assn., Walensky said he hoped for the best, but also warned of the worst case scenario – that people will stop wearing masks and distance themselves physically too soon and that many will declare prematurely that ‘already I am sick of the pandemic and I will not be vaccinated.
“How that will depend on 330 million people,” said Walensky. “Because although I’m really hopeful about what can happen in March and April, I really know it can go wrong – so fast. And we saw that in November. We saw this in December. We saw what can happen. “
Dr. Annabelle of St. Maurice, a pediatric infectious disease specialist at UCLA, said she sympathized with employees trying to walk a fine line between keeping morale high and not making people feel so optimistic that they would lower their health. guard.
In Los Angeles in particular, the numbers have improved dramatically, she said, but they remain almost as high as during the deadly summer surge.
“It’s a reason to celebrate, and you want people to celebrate it, but you want them to do it physically at a distance and wearing a mask,” she said.