A modeling study on the new coronavirus warns that intermittent periods of social distancing may need to persist into 2022 in the United States to keep the surge of people severely sickened by Covid-19 from overwhelming the health care system.
The research, published Tuesday in the journal Science, looked at a range of scenarios for how the SARS-CoV-2 virus will spread over the next five years. Those scenarios included variables like whether people who are infected develop short-term immunity — less than a year — or longer-term protection. But, overall, the research concludes it is unlikely that life will return any time soon to the way it was before the virus’ emergence.
The researchers, from Harvard University’s T.H. Chan School of Public Health, acknowledged the economic fallout from the response to the virus has been profound. And they stressed they were not advocating one course of action over another.
“Our goal in modeling such policies is not to endorse them but to identify likely trajectories of the epidemic under alternative approaches,” they wrote. “We do not take a position on the advisability of these scenarios given the economic burden that sustained distancing may impose, but we note the potentially catastrophic burden on the healthcare system that is predicted if distancing is poorly effective and-or not sustained for long enough.”
The authors suggest a number of factors will play a major role in the path the disease will take over the coming years — if transmission subsides in summer and resurges in winter, if there is some immunity induced by infection and how long it lasts, and whether people get any cross-protective immunity from having been infected with related human coronaviruses that cause common colds.
In terms of the latter, they suggest if infection with the human coronaviruses, HKU1 and OC43, gives some protection again SARS-CoV-2, it could appear that transmission of the new virus was tapering off. But a return within a few years would be expected, perhaps by 2024, they suggested. The two human coronaviruses induce only short-term immunity — less than a year — in infected people.
If SARS-CoV-2 triggers immunity of a similarly transient nature, annual wintertime waves of infection might be expected, they said. If the immunity lasts longer, the time between surges of cases might be a couple of years, or more.
And if immunity is permanent, the pandemic might burn itself out by about 2025, they said. The researchers suggested, though, that that scenario is unlikely.
The model predicts that a one-time social distancing effort of the type currently being employed in most parts of the country will not stop transmission of the virus. If treatments are developed that can prevent Covid-19 patients from progressing to severe disease or if a vaccine is developed, movement restrictions could be loosened without health care capacity being overwhelmed, the researchers said.
Likewise, increasing the capacity for intensive care beds could also allow a community to loosen its restrictions, as long as it could cope with the severe cases the increased spread would generate. That could speed progress towards herd immunity — the point where enough people have some immunity that transmission should drop off, they said. Without these extra tools, though, transmission will resurge once controls are loosened, the authors warned.
“So I think distancing interventions of some sort are going to have to continue, hopefully lightened and in conjunction with other interventions,” said Marc Lipsitch, a leading infectious diseases epidemiologist and senior author of the study.
Infectious diseases epidemiologist Caitlin Rivers said the modeling work will be useful for public health officials and disease experts trying to plan for the continued response to the virus.
“What this is saying is that SARS-CoV-2 will stay with us through 2022, that it’s not going to die down to nothing in the summer. So I think it’s helpful for thinking what interventions are sustainable and effective,” said Rivers, an assistant professor of epidemiology at the Johns Hopkins Center for Health Security. “If we knew that we only had to make it through another two weeks, we might make different decisions than understanding that this is a threat that will be with us for many months,” she added.
While acknowledging that intermittent periods of distancing over several years “is obviously a very long time,’’ Lipsitch said loosened restrictions could come sooner if scientists discovered that a lot more people have been infected already and have some immunity. He and his co-authors stressed how critical it is to conduct long-term serology studies designed to map out human immune responses to the virus over time.
“On the other hand, there are some indications coming out at the moment that not every case of Covid-19 infection … generates a robust immune response, which would mean that the build up of herd immunity is slower than its anticipated here,” he added.
The study does not look at whether imposing social distancing only among certain high-risk groups — including older adults and those with serious underlying health problems — might keep the number of severe cases low enough that health systems would be able to handle them.
Another of the authors, Yonatan Grad, said tailoring restrictions to high-risk groups would be an important idea. But one would also need to factor in whether people who had been freed from social distancing restrictions would then interact with people in those restricted groups — something that might depend on the composition of individual households, he said.
Lipsitch acknowledged that delaying the development of herd immunity — effectively keeping large numbers of people susceptible to the virus by shielding them from infection — runs a risk of creating a larger wave of illness later, if controls are eased during a time when the virus transmits more easily, as it is expected to do during winter months. But delaying infections buys time, he said.
“Pushing bad things out into the future is something we want to do because we should know more about treatments, we may be closer to a vaccine,” he said. “So there is some benefit to delay, but it might be offset in the seasonal scenario where we push the peak into the high transmission time around the winter.”
The entire thing is a hoax constructed by Bill Gates see Event 201 and ID 2020. The US was taken over without anyone firing a shot. Even the doctor that researched this virus is on social media saying that this is. true and you can’t even catch it unless it is injected. Look her up Dr. Judy Mikovits American Researcher if you want TRUTH!
Every American should watch this video to know just how distorted what they have been told really is https://www.youtube.com/watch?v=0wTiCxXgrJw
This is outrageous. Such articles are clearly reckless and irresponsible reporting. With developments each day, week , month , things can change in a heartbeat. Numbers show ( here in the US ) we are either at or on the downside of the curve right now on 4-16-20 (depending upon where one obtains data). I get it . It is because of the non pharmaceutic behavior that we are on the spread mitigating downtrend. By the “S” curve factor in any spread or pandemic, this will reduce in numbers substantially in the ensuing few months. This is so manifested clearly by the history of the outbreak other countries such as China and Italy. Furthermore, developments as we speak in new RX treatments that will and in all probability illuminate the need entirely
for non pharmaceutic public spread mitigation measures. It is reasonable to say that this will all be behind people long before 2022. It is absurd to make such a prediction for 1 yer and a half to 2 years from now. The writer will have “egg on her face” for such article. Just watch. No media should make any prediction at all as it is too uncertain right now. Shut up and quit freaking out the public to these dreaded social behaviors that will be long gone by then.
Thank you for saying what needed to be said. Couldn’t agree more!
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