COVID-19: A new drug is tested, and other top science stories of the week

Researchers at Fudan University in Shanghai analysed blood samples from 175 recovered coronavirus patients after they were discharged from hospital and found surprisingly low levels of antibodies against the virus.

Around 30% of patients had antibody levels that were so low, researchers suspect they might not be protected against reinfection.

The fear is that if a proportion of the population does not build up immunity to the virus, herd immunity could be compromised. Additionally, scientists developing vaccines would need to consider how to generate a significant and lasting antibody response to provide sufficient protection.

The preliminary results are not yet published in a journal, and further research is necessary to examine whether individuals with low levels of antibodies are at risk of reinfection.

This week marked the beginning of another clinical trial of a potential COVID-19 therapy, but rather unusually, this one targets human cells rather than the virus.

Last month, scientists showed that the drug, camostat mesylate, can prevent the novel coronavirus, SARS-CoV-2, from infecting lung cells in the lab. Viruses rely on the machinery inside human “host” cells to survive and replicate, so preventing the virus from entering human cells could stop the virus in its tracks.

It normally takes years before drugs can enter human clinical trials, but because camostat mesylate is already approved for use in some patients with pancreatitis – a potentially fatal inflammation of the pancreas – scientists were able to start trials much sooner.

It isn’t yet known whether the drug will reach the lung cells of that patients that the virus targets, but the researchers at Aarhus University in Denmark who are conducting the trial hope to know whether the drug is effective within three months.

Sewage treatment facilities hit the headlines this week as it transpired that SARS-CoV-2 genetic material — viral RNA — appears in wastewater, raising hopes of a new way to track the severity of the outbreak.

It is hoped that wastewater testing could also be used as an early-warning system of a second wave of infections, and help governments make decisions about when to implement and loosen lockdown measures.

More than a dozen research groups worldwide have started analysing wastewater for the new coronavirus to estimate the total number of infections in a community, given that many people will not experience severe symptoms, or be tested.

Studies have shown that viral RNA can appear in faeces within three days of infection, giving a much closer to real-time analysis of infection rate, compared to clinical tests which can have a lag time of weeks.