Coronavirus latest: pandemic could have killed 40 million without any action

Here’s the latest news on the pandemic.

27 March 15:00 GMT — Virus could have killed 40 million without global response

The COVID-19 pandemic could have infected 90% of the world’s population and killed 40.6 million people if no mitigation measures were put in place to combat it, according to estimates from an influential modelling group at Imperial College London.

The report from the Imperial College COVID-19 Response Team, published on 26 March, highlights the importance of acting early to suppress the outbreak. The analysis says that introducing social distancing, testing and isolating infected people would cut worldwide deaths to 1.9 million, if carried out when each country’s fatality rate is 0.2 per 100,000 people per week. Implementing these measures only when the death rate reaches 1.6 per 100,000 people per week leads to 10.5 million lives lost globally, it finds. According to Nature’s analysis of death rates from Our World in Data — counting each day at the centre of a rolling weekly window of deaths — Italy hit the 0.2 threshold on 2–3 March, the United Kingdom on 17 March, and the United States on 22 March.

The report did not quantify the social and economic impact of such policies.

The analysis was published on the same day that UK Prime Minister Boris Johnson and the nation’s health minister, Matt Hancock, tested positive for the coronavirus. In a video address to the nation, Johnson said he had only mild symptoms and would continue to work remotely while isolating for 14 days.

27 March 03:00 GMT — Global infections number half a million

The number of confirmed COVID-19 cases around the world crossed 500,000 on 26 March, according to statistics compiled by the Center for Systems Science and Engineering at Johns Hopkins University in Baltimore, Maryland. The pandemic currently spans 175 countries and every inhabited continent.

By the end of the day on 26 March, the United States had overtaken China for the highest number of confirmed cases. Italy is also poised to surpass China in the coming days. Italy and Spain now have the two highest death tolls, with Italy accounting for more than one-third of the global total.

COVID-19 has claimed the lives of nearly 23,000 people. More than 120,000 have recovered from the disease.

Source: World Health Organization

26 March 13:15 GMT — United Kingdom pledges to roll out extensive antibody testing

The United Kingdom could begin large-scale testing for coronavirus antibodies within days, government officials have said. If the roll-out goes ahead as planned, the country could become the first to implement at-home testing on this scale — but researchers caution that properly validating the accuracy of such tests and manufacturing them in large quantities presents a significant challenge.

On 25 March, a UK government official said that the country had ordered 3.5 million ‘finger-prick’ tests and planned to order millions more. The test will analyse drops of blood for antibodies that show whether a person has previously been infected with the coronavirus that causes COVID-19. This will show who might now be immune and aid researchers in understanding the virus’s spread. These ‘serological tests’ should become available to the public in days rather than weeks or months, said Sharon Peacock, director of the national infection service at Public Health England (PHE), a UK health agency. Peacock suggested that the bulk of the UK tests, which will be available to buy from Amazon and pharmacies to perform at home, had not yet arrived.

Most tests to diagnose coronavirus infection have involved laboratory-based testing using the technique known as PCR, which checks for active infection. But an urgent goal has been to develop serological tests, which can detect past infection. These are now being deployed worldwide. Singapore, for instance, has been using the tests for more than a month to trace known infections and monitor at-risk populations.

But thoroughly evaluating the efficacy of the tests and the rate of false positives is essential, says Robert Garry, a virologist at Tulane University School of Medicine in New Orleans, Louisiana, whose team is developing its own serological test.

The blood test will need to distinguish between antibodies against the COVID-19 virus and those against other seasonal coronaviruses to which people are commonly exposed, he says. “I would expect the false-positive rate to be very high because of this prior exposure — unless they figured out how to make the serological test very specific,” he says. Garry says that for a validated test, he would expect a false-positive threshold of less than 5% — meaning fewer than 5 out of 100 people without the antibodies test positive — although he could see that being relaxed to 10%. Even with ready access to clinical samples, understanding false-positive levels on this timescale would require a massive effort, says Garry.

PHE is evaluating the tests to ensure they work as claimed, said Peacock, who anticipates this will be done by the end of the week.

But supply is likely to remain limited, says David Wraith, an immunologist at the University of Birmingham, UK. It will be challenging for companies to manufacture millions of tests and for any one government to secure so many during a global pandemic, meaning that health-care workers must be given priority access, he says.

It is not clear who is developing the UK test. A PHE spokesperson said the agency was talking to a range of companies. Peacock added that highly vulnerable members of the public who test positive will also require further tests before they can resume normal life.