According to the study, while temporary social isolation can remove critical cases from hospital capacity, the infection will reappear once these measures are lifted.
Research suggests that this will overwhelm hospitals as social distance will have to be maintained intermittently until 2022.
The new modeling study indicates that the total incidence of the virus until 2025 will essentially depend on the duration of human immunity – which scientists currently know little about.
Researchers say that longitudinal serological studies are urgently needed to determine the extent of population immunity, whether immunity declines and at what rate.
Experts believe that Covid-19 is unlikely to follow its nearest cousin, Sars-CoV-1, and be wiped out by intensive public health measures after causing a brief pandemic.
Instead, the transmission could resemble that of pandemic influenza by circulating seasonally.
Stephen Kissler, postdoctoral fellow at Harvard TH Chan School of Public Health, Grad Lab, Department of Immunology and Infectious Diseases, and colleagues, used data on the seasonality of other known human coronaviruses – assuming some cross-immunity between them and Sars-CoV- 2 – build a model of multi-year interactions.
They used the model to study how long social distancing measures must remain in place to maintain control of Covid-19 projecting its potential dynamics over the next five years.
Based on their simulations, they claim that the key factor modulating the incidence of the virus in the coming years is the rate of decline in viral immunity – something that scientists have yet to determine.
Researchers report that in all simulated scenarios, including punctual and intermittent social distancing, infections reappear when the simulated social distancing measures are lifted.
Their model indicates that when social distancing is relaxed when the transmissibility of the virus increases in autumn, an intense winter epidemic can occur, overlapping the flu season and exceeding the capacity of hospitals.
Another scenario suggests that a resurgence of Covid-19 may occur in the future until 2025.
Researchers say new treatments may alleviate the need for strict social distancing, but in the absence of these, monitoring and intermittent distancing may need to be maintained until 2022.
This would give hospitals time to increase the capacity for intensive care while allowing the immunity of the population to build up.
The authors write in the journal Science: “Our objective in modeling such policies is not to approve them but to identify the likely trajectories of the epidemic under alternative approaches. “
They say, “Additional interventions, including increased capacity for intensive care and effective therapy, would improve the success of intermittent distance and accelerate the acquisition of collective immunity.
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“Longitudinal serological studies are urgently needed to determine the extent and duration of immunity to Sars-CoV-2.
“Even in the event of an apparent elimination, Sars-CoV-2 surveillance should be maintained since a resurgence of the contagion could be possible until 2024.”
Mark Woolhouse, professor of epidemiology of infectious diseases at the University of Edinburgh, said, “This is an excellent study that uses mathematical models to explore the dynamics of Covid-19 over a period of several years. , unlike previously published studies that focused on the coming weeks or months.
“It is important to recognize that this is a model. It is consistent with current data but is nevertheless based on a series of assumptions – for example on acquired immunity – which remain to be confirmed.
“The study should therefore be seen as suggesting possible scenarios rather than making firm forecasts. “