The latest World Health Organization (WHO) briefing on the coronavirus pandemic has underlined confusion over the risk of reinfection from patients who may appear to have staged a full recovery. 

Officials say initial research suggests that not all of those who recover from illness develop enough antibodies to fight off a second infection. As such, they remain vulnerable to a second attack.

Speaking at the organisation's daily briefing in Geneva, the WHO's COVID-19 technical lead Maria van Kerkhove stated "We do not have a full picture of what immunity looks like. Until we do we cannot give a complete answer."  

She added that a recent untested study in Shanghai, which examined the blood plasma of 175 recovered patients, found that while some appeared to have staged a strong antibody response, others had done less well. More research is planned into the immune response of some of the 300,000 people who have recovered globally from the coronavirus. 

"The information is mixed," Van Kerkhove said. "We need much more information from recovered patients... we need to better understand what that antibody response is."

'We do not have the answers'

Speaking at the briefing, WHO's emergencies program executive director Michael Ryan said "With regards to recovery and then reinfection, I believe we do not have the answers to that. That is an unknown."

Ryan noted that "there are cases where someone doesn't clear the virus entirely from their system... and the virus can come back and that is seen as a reactivation," adding "there are other situations where someone clears the virus but develops a second infection, a bacterial infection." 

The WHO also used Monday's press briefing to warn about the risks of an early end to social distancing as a means of containing infection risk. Denmark, Norway and Austria are among the European nations to announce plans for a partial lifting of lockdown restrictions, with shops and businesses reopening and children returning to school within the next few weeks.

Speaking at the briefing, WHO director-general Tedros Adhanom Ghebreyesus cautioned that only countries with strong health infrastructure in place should consider such measures. 

"The way down is much slower than the way up," he said. "Control measures can only be lifted if the right public health measures are in place, including significant capacity for contract tracing."

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