Chances are that we will have to live with the one and a half meter society for years to come. We may need to take corona outbreaks into account by 2025, a study by a leading group of Harvard researchers warns.
The study, published in the scientific journal Science, outlines different scenarios about the spread of the virus and how long it can last. The study concludes that one lockdown several months is not enough to contain the corona pandemic. As long as there is no vaccine, there will be ‘follow-on peaks’, which without measures can become larger than the current outbreak. One of the scenarios takes into account revivals of the disease until 2025.
Nor does it make sense that the epidemic would have been curbed by one lockdown period, according to Harvard professor of epidemiology and co-author Marc Lipsitch. “That is not consistent with what we know about the spread of infections.” In all the scenarios the researchers looked at (except for an infinite lockdown or if everyone becomes immune), it was found that the virus will resurface if the measures are relaxed.
Immunity not forever
The researchers put data on three coronaviruses, including the new coronavirus, into mathematical models that took into account different variables, such as how many people build up immunity and whether there is a seasonal effect. The calculations were about the situation in the US, but probably also apply to countries such as the Netherlands, Lipsitch expects.
How strongly the virus can come back depends on how many people have already had the disease and to what extent they have been able to build up immunity. There is a chance that people who have been ill become susceptible again after a while, as is the case with many other respiratory viruses. That could lead to the virus returning every other year or every few years, the Harvard researchers say.
Erasmus MC virologist Marion Koopmans previously said that permanent immunity to a respiratory virus is rare. “What we expect and hope is that covid-19 is milder in people who have already been infected.”
Few seasonal influences
The researchers are disappointing people who think that the warm weather will put the virus out in the summer: “Transmission of the virus in the summer is slowing down, but that is not enough,” Lipsitch said at a news conference last week. This is also evident from the fact that the virus simply spread in the southern hemisphere, where it was summer.
After that, in the autumn and winter period, the virus will resurface in all its severity without measures, Lipsitch thinks. “Most people are still susceptible to infection,” he says.
The researchers hope for a vaccine. Until there is, measures continue to be needed, according to their models for a long continuous period or with interruptions in which the measures are temporarily relaxed.
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