Coronavirus has accelerated scientific developments to a wartime pace. Here are some of the significant advances this week.
Antibody testing for all is on the horizon
Cheap, reliable antibody tests that reveal whether someone has previously had Covid-19 are viewed as crucial for managing the next phase of the pandemic. Population-level screening can gauge the overall level of immunity and can allow people to incrementally return to work. Various teams around the world are already using lab-based antibody testing, but this is challenging to scale up, partly because the tests need to be performed a few weeks after infection. In parallel, companies have been working on home-testing kits that work something like a pregnancy test. This week, the UK government signalled it thought such tests could be reliable enough, announcing it had bought 3.5m testing kits, with a view to making them available first to healthcare workers, and then to the public through high street chemists or Amazon delivery. An unnamed prototype is being validated in Oxford this week and the proposal still hinges on the tests’ performance. “The one thing that is worse than no test is a bad test,” Chris Whitty, England’s chief medical officer, said on Wednesday. In Spain, the government was forced to withdraw 9,000 Chinese-made coronavirus testing kits from use after it emerged that they had an accurate detection rate of just 30%.
Covid-19 might affect your sense of smell and taste
Anecdotal reports have been circulating for weeks that Covid-19 can cause people to lose their sense of smell. This week, the idea gained credibility with the British Association of Otorhinolaryngology suggesting that so-called anosmia could be a useful symptom for screening for the virus, based on reports from South Korea, China and Italy, and higher than usual numbers reporting the complaint in UK clinics. On Monday, World Health Organization officials also said they were also looking into the possible link. “We are reaching out to a number of countries and looking at the cases that have already been reported to see if this is a common feature,” said Maria Van Kerkhove, the head of the WHO’s emerging diseases and zoonoses unit. “We don’t have the answer to that yet.”
The good news is that even if the coronavirus kills off some of your olfactory cells, the nose lining contains stem cells to make replacements. “Colleagues in Italy report encouraging rates of recovery, with many patients reporting return of sense of smell within seven to 14 days,” the British association advises. “This seems to be the experience of patients in the UK.”
The virus appears to be very stable
Coronaviruses, in general, don’t tend to mutate rapidly and this week scientists provided further reassurance that this is true for Covid-19. A team at Johns Hopkins University analysed 1,000 samples and, according to the Washington Post, found only four to 10 genetic differences between the strains circulating in the US and the original virus that was isolated from patients in Wuhan. An Italian analysis, also out this week, reached similar conclusions. This suggests that if an effective vaccine is found it should continue to work for some time. However, there is still an open question about how stable the human immune response is to Covid-19, and whether people who are infected once will be protected against reinfection long into the future.
Hopes that life could get back to normal some time soon were dampened this week with models suggesting that lockdown measures need to remain in place for months to have their intended effect. A paper published in the Lancet suggested that if controls in Wuhan had been relaxed in early March, when case numbers dramatically dropped, the city would already be ramping up towards a fresh outbreak in June. China’s decision to maintain its lockdown until early April was estimated to reduce the average number of new infections by the end of 2020 by 24%. The restrictions currently in place in the UK will be reviewed on 13 April.
Men appear to be more susceptible to Covid-19
Evidence is growing that men are more likely to die from the disease than women. This was first observed in China, where the fatality rate was around 2.8% for men and 1.7% for women and the pattern has been mirrored as successive countries have released data. This week Spain reported that around twice as many men as women had died. The difference was initially put down to high rates of male smoking in China – about half of men smoke compared with just 2% of women. However, as the same trend has been replicated in countries with more equal proportions of male and female smokers, scientists are starting to consider other possibilities, including that women’s immune systems may be better able to overcome the virus. Serological studies from China, tracking the immune response throughout the course of infection, should soon start to provide some answers about why men appear more vulnerable and whether behaviour, lifestyle factors or biology is the leading factor.