When will it end?

With the lockdown in place, scientists are tackling the next big question: how to ease restrictions without triggering a new wave of infections. By Tony Allen-Mills and Andrew Gregory.

Early in his long career as a virus hunter, David Heymann found himself deep in the equatorial heart of Africa, heading for a Belgian hospital in the country then known as Zaire, now the Democratic Republic of the Congo. Darkness had fallen by the time he arrived at the village where a deadly infection had broken out.

The headlights of his vehicle picked out a group of Red Cross workers burying bodies in a makeshift cemetery. It was 1976, his first encounter with the previously unknown virus that an American-Belgian-British team would later name Ebola.

Today Heymann is 74 and still confronting the horrors of new and virulent diseases. As chairman of the advisory group on emergency programmes at the World Health Organisation (WHO), he spent much of last week preparing guidance for countries that have imposed lockdowns to control the spread of Covid-19, but remain unsure about when and how safely those lockdowns might be unlocked.

Born in America and now based in London, Heymann was known for a long time as a ‘‘disease cowboy’’, saddling up for action at every sign of Ebola, smallpox, monkeypox, measles, tuberculosis and now Covid-19. He lived for 13 years in Africa before moving to Geneva with the WHO. He later became professor of infectious disease epidemiology at the London School of Hygiene and Tropical Medicine, and served for five years as chairman of Public Health England.

Then, 10 days ago, one of the world’s foremost experts on infectious disease did something that many governments have been urging their citizens to avoid. He moved to France to look after his grandchildren, seemingly putting himself at a greatly increased risk of local household infection.

‘‘Oh, I know I’m in a vulnerable age group,’’ Heymann laughed last week from his temporary home close to the Swiss border near Geneva. ‘‘But it’s a very unique situation.’’ He has three children; his two sons are both doctors. One is married to another doctor. His daughter is a lawyer married to yet another doctor. All four doctors are working long hours in emergency services in Geneva.

Heymann’s grandchildren are stuck at home, doing their schooling by internet. Their grandfather is happy to supervise them, knowing that, if he starts feeling ill, he isn’t going to lack for care.

Indeed, far from feeling ill,

Heymann goes jogging for an hour each day and is steaming ahead on his study of lockdown strategies. He has held two video meetings with expert colleagues and expects the WHO to issue formal guidance on lockdowns shortly.

Last week he and other experts discussed the next phase of the crisis, and what we have learnt about the virus still laying waste to families and businesses around the globe.

So, how effective are lockdowns proving?

‘‘They were certainly effective in China,’’ he says. ‘‘There is no question they decreased transmission.’’ There are still occasionally new cases in Wuhan, the origin of the current pandemic, but most of those now reported in China appear to have been imported by visitors or returning citizens.

China’s success in ‘‘flattening the curve’’ of infection has encouraged it to begin unlocking the industrial sector, a move being closely watched around the world. ‘‘They are doing it very cautiously to see what happens,’’ says Heymann, who spoke to the head of the Chinese centre for disease control last week. ‘‘Then they will begin to unlock other sectors if they see it’s successful.’’

Other countries have refined their lockdown strategies according to their capacity for testing for infection or individual national characteristics.

The evidence from Singapore persuaded authorities early on that schools were not a significant source of infection. ‘‘They have never closed their schools,’’ says Heymann. ‘‘That may be a hint for other countries to look at.’’

While the goal of wellprepared Asian countries was broadly to restrict the outbreak, the objective in European countries such as Italy, Spain and Britain has been markedly different: to prevent underequipped and badly stretched health services from being overwhelmed.

Several significant outliers have emerged, notably Sweden, which shunned shutdowns in favour of public information programmes, protection of the elderly and faith in sensible Scandinavian behaviour. But a sudden spike in cases last week – with deaths jumping from 41 to 66 in one 24-hour period – has sparked concern that it may have seriously miscalculated.

Germany has also taken a different route, ploughing vast technological resources into testing and contact tracing to ‘‘try to interrupt the chains of transmission’’, says Heymann. Germany currently has four times as many confirmed cases as Britain, but half as many deaths. It only recently began introducing lockdown measures.

‘‘The jury is still out as to which strategy or strategies work best, but underlying them all is the need to get populations to collaborate with the outbreak response and understand how to protect themselves and others,’’ Heymann says.

Is Britain’s lockdown working?

British researchers caution that more time will be needed to judge the effectiveness of the measures introduced the weekend before last. ‘‘We now enter a phase of careful monitoring,’’ says Professor Mark Woolhouse, an infectious disease specialist at Edinburgh

‘‘The jury is still out as to which strategy or strategies work best, but underlying them all is the need to get populations to collaborate . . . and understand how to protect themselves and others.’’ David Heymann