Combat coronavirus through mass testing, say scientists

Mass testing is the best approach to tackling coronavirus, according to new research.

Physicists at the University of Aberdeen found severe lockdowns will not create enough “herd immunity” to eradicate Covid-19.

They stressed the importance of “thorough testing combined with contact tracing, isolation of infected individuals and social distancing”.

Lockdowns are probably the most effective way to delay epidemics until faster and more thorough testing or a vaccine is available, they added.

The researchers modelled infections using data from from the early stages of the outbreak in the UK, Italy, Spain, Germany and Hubei province in China.

In the specific outbreaks they modelled, they found that only around 8% of the population will have been exposed to the infection, which they said will not lead to the levels of herd immunity required to control and defeat the virus.

The researchers said such a low infection rate could mean that if and when restrictions are lifted, the virus could re-emerge.

The scientists said testing – including people who have not shown any symptoms – is essential to combating the spread of coronavirus.

Dr Francisco Perez-Reche and Professor Norval Strachan found around 50-80% of the infected population in their models were “silent carriers” who could spread the disease but showed no symptoms.

They predict that in time, a partial relaxation of ongoing lockdowns could keep daily deaths from Covid-19 to fewer than 100 a day.

Dr Perez-Reche said: “Our results demonstrate that the current suppression strategies being employed in Germany, Hubei, Italy, Spain and the UK will not facilitate sufficient levels of herd immunity in the population that would control and eventually eradicate the virus.

“This leaves the risk of re-emergence of the virus once suppression strategies are lifted, similar to second waves of infection observed in 1918 influenza epidemics.

“We predict, however, that partial relaxation of ongoing lockdowns could keep the number of daily deaths to less than 100.”

Prof Strachan said: “Unreported cases act as silent carriers and control strategies would need to account for them or be prone to the risk of re-emergence or ineffective suppression of spread.

“For instance, we predict that isolation of infected individuals can have a limited impact on the suppression of spread unless it includes silent carriers that are currently missed by most countries.”

Dr Perez-Reche added: “In line with previous suggestions, we suggest that thorough testing combined with contact tracing, isolation of infected individuals and social distancing can be more effective to suppress Covid-19 spread than severe lockdowns.

“At present, however, lockdowns are probably the most effective way to delay epidemics until more effective pharmaceutical or non-pharmaceutical interventions – i.e. fast and thorough testing – become feasible.”