Crucial piece of Covid-19 science still missing Government‘s top advisor tells ITV News

At last, our collective efforts are starting to pay off.

More than three weeks of social distancing is showing a clear signal in the Covid-19 data; cases are flattening out, admissions to hospitals are falling.

The government insists the decision of where to go next must be “science-led”.

However, ITV News has learned that a key piece of that science is still missing.

Despite a month of effort, data on the number of people in the general population may have been infected with the virus, and therefore might be immune is still unavailable.

An accurate picture of how who has already had the virus and whether they are now immune — known as serological testing — is crucial to knowing when it might be safe to ease lockdown measures.

  • ITV News Science Editor Tom Clarke explains how scientists are working towards finding out how many have been affected by coronavirus

At Thursday's Downing Street Covid-19 press conference the Chief Medical Officer Professor, Chris Whitty, told me they are currently missing the information needed.

“We're moving very fast in this area scientifically, but we are definitely not there in either of the issues of getting serology or getting the sampling frame, but will probably have a crude ranging idea fairly soon," Mr Whitty said.

Serological testing has issues relating to science. Credit: PA

Unlike the delays over swab testing for the virus, the problems with serological testing aren’t based on policy but science.

None of the existing tests being used in laboratories to look for virus antibodies are giving good results.

They’re either returning false positive results because they react to other coronaviruses that cause the common cold, or are unable to detect antibodies in people who are known to have tested positive.

“Until we get really good tests - and we don’t have really good tests - we’re not going to be able to have any confidence in how we go about this process — it’s going to be a really difficult tricky problem,” says Professor Calum Semple at the University of Liverpool.

This situation could improve in the coming weeks, however.

It takes about 21 days for people to produce antibodies to the virus.

As more people recover from the virus its hoped surveillance for infections in the community could start to show more useful results.

As the Chief Medical Officer told me: “[We] will probably have a crude ranging idea fairly soon."

Coronavirus: Everything you need to know