COVID19 immunity can last for 2 years but social distancing must till 2022: Harvard Research
Members of a medical team surveying a house in Srinagar (File Photo KM/Umar Ganie)
Srinagar: The world may be in for a long haul as a Harvard University research calls for intermittent social distancing till 2022 while also projecting recurrent coronavirus outbreaks each year after the ongoing initial wave of infection.
The study ‘Projecting the transmission dynamics of SARS-CoV-2 through the postpandemic period’ published yesterday (April 14) by five Harvard researchers says that “recurrent wintertime outbreaks of SARS-CoV-2 will probably occur after the initial, most severe pandemic wave.”
“Absent other interventions, a key metric for the success of social distancing is whether critical care capacities are exceeded. To avoid this, prolonged or intermittent social distancing may be necessary into 2022,” reads the study available on Science Magazine, a PDF copy of which was accessed by The Kashmir Monitor.
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the official WHO name given to the virus that causes COVID-19 disease. Till Wednesday, the virus contracted over two million people globally and killed more than 1.28 lakh in at least 185 countries.
Making a very important statement, the study says that the coronavirus immunity may last for at least two years but suggests social distancing measures be kept in place.
“In our assessment of control measures in the initial pandemic period, we assumed that SARS-CoV-2 infection induces immunity that lasts for at least two years, but social distancing measures may need to be extended if SARS-CoV-2 immunity wanes more rapidly,” it says.
It adds that even if novel coronavirus immunity only lasts for two years, mild (30%) cross-immunity from two other coronaviruses (HCoV-OC43 and HCoV-HKU1) could effectively eliminate the transmission of SARS-CoV-2 for up to three years before a resurgence in 2024, as long as SARS-CoV-2 does not fully die out.
“So a period of sustained or intermittent social distancing will almost certainly be necessary,” the study says.
“To implement intermittent social distancing, it will be necessary to carry out widespread viral testing for surveillance to monitor when the prevalence thresholds that trigger the beginning or end of distancing have been crossed.”
A vaccine, it says, would accelerate the accumulation of immunity in the population, reducing the overall length of the epidemic and averting infections that might have resulted in a need for critical care.
But the same, it says, will take months at best.
“Coronavirus has demonstrated an ability to challenge robust healthcare systems, and the development and widespread adoption of pharmaceutical interventions will take months at best.”
The researchers have also pointed out that if there have been many undocumented immunizing infections, the herd immunity threshold may be reached sooner.
Herd immunity happens when many people in a community become immune to an infectious disease that it stops the disease from spreading.
The researchers acknowledge that prolonged distancing, even if intermittent, is likely to have profoundly negative economic, social, and educational consequences.
“Our goal in modelling such policies is not to endorse them but to identify likely trajectories of the epidemic under alternative approaches, identify complementary interventions such as expanding ICU capacity and identifying treatments to reduce ICU demand, and to spur innovative ideas to expand the list of options to bring the pandemic under long-term control.”
The study concludes that the total incidence of COVID-19 illness over the next five years will depend critically upon whether or not it enters into regular circulation after the initial pandemic wave, which in turn depends primarily upon the duration of immunity that SARS-CoV-2 infection imparts.