When, and How, Does the Coronavirus Pandemic End?

Bloomberg

With confirmed cases of Covid-19 globally exceeding 1 million and more countries going into lockdown to slow the pandemic, the emerging question is: “When will this all end?” The answer depends in large part on uncertainties about the novel coronavirus that causes the disease, including whether you can get it more than once and how quickly the world’s scientists might produce a vaccine. The cost and benefits of a prolonged shutdown and what different countries can afford, from both an economic and political standpoint, are factors, too.

1. So how does this end?

There’s a consensus that the pandemic will only end with the establishment of so-called herd immunity. That occurs when enough people in a community are protected from a pathogen that it can’t take hold and dies out. There are two paths to that outcome. One is immunization. Researchers would have to develop a vaccine that proves safe and effective against the coronavirus, and health authorities would have to get it to a sufficient number of people. The second path to herd immunity is grimmer: It can also come about after a large portion of a community has been infected with a pathogen and develops resistance to it that way.

2. How do we manage until then?

For many countries, the strategy is to lock down movement to dramatically slow the spread, closing businesses and schools, banning gatherings and keeping people at home. The idea is to prevent a huge burst of infections that overwhelms the medical system, causing excessive deaths as care is rationed. “Flattening the curve” staggers cases over a longer period of time and buys authorities and health-care providers time to mobilize — to build capacity for testing, for tracking down contacts of those who are infected, and for treating the sick, by expanding hospital facilities, including ventilators and intensive-care units.

3. When can restrictions loosen?

The public shouldn’t expect life to return to normal quickly. Lifting restrictions too early risks inviting a new spike. Authorities in China began to re-open the city of Wuhan, where the pandemic began, two months after it was sealed off from the world, when transmission had virtually halted. But China’s measures were stricter than anywhere else so far, and at least one county has gone back to a lockdown. England’s deputy chief medical officer, Jenny Harries, said lockdown measures there need to last two, three or, ideally, up to six months. Annelies Wilder-Smith, a professor of emerging infectious diseases at the London School of Hygiene and Tropical Medicine, recommends restrictions stay in place until daily cases drop consistently over at least two weeks.

4. Then what?

A road map authored by a group of U.S. health specialists including former Food and Drug Administration commissioner Scott Gottlieb calls for an intermediate stage in which schools and businesses would reopen but gatherings would still be limited. People would continue to be encouraged to keep at a distance from one another, and those at high risk would be advised to limit their time in public. If cases begin to rise again, restrictions would be tightened. Their report, published by the pro-business American Enterprise Institute, is arguably more optimistic than the future envisioned by researchers at Imperial College London. Their models suggest that for at least two-thirds of the time until herd immunity is established, all households would need to reduce contact with schools, workplaces or the public by 75%. In any case, the widespread availability of testing is important in this stage. At the heart of the U.S. plan: at least 750,000 tests per week.

5. Why is testing so important?

This virus is wreaking so much havoc, not because it’s especially lethal, but because it’s insidious; many who are infected are well enough to go about their daily business, unwittingly spreading it to others. That makes it vital to test for infection widely in the population, and to test everyone with symptoms. That way, those who are infectious can be put in isolation and everyone they’ve had close contact with while contagious can be tracked down, tested and if necessary isolated as well, limiting the spread in the community. Another kind of test looks for antibodies to see who has already beaten the virus and is thus unlikely to be re-infected, at least for a time. Once widely available, such tests might enable people who test positive for antibodies to move about more freely.

6. Why does where you are matter?

Authoritarian countries such as China can impose stricter controls on movement and more intrusive means of surveillance, such as house-to-house fever checks, tracing and enforcement of quarantines, and are less vulnerable to pressure from businesses and popular opinion. That gives them powerful tools to keep the virus in check, so long as they are vigilant against imported cases. That’s a more difficult proposition for other nations. The poorest countries can less easily afford the economic losses caused by prolonged restrictions, and often don’t have the health infrastructure for extensive surveillance.

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Source: James Paton | Bloomberg

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