Recovered COVID-19 patients may help cut risk from lifting lockdown: Study

WASHINGTON DC: Patients who have recovered from COVID-19 may help in reducing the pandemic's infection rate as lockdown measures are eased to improve the economy in several parts of the world, a study says.

Researchers, including those from the Georgia Institute of Technology in the US, said the presumed immunity of those who have recovered from the novel Coronavirus infection could allow them to safely substitute for susceptible people in certain high-contact occupations such as healthcare.

They anticipate that this "shield immunity," would protect against short-term reinfection and allow recovered patients to expand their interactions with infected and susceptible people.

According to the study, published in the journal Nature Medicine, this could potentially reduce overall transmission rates when interactions are permitted to expand.

The scientists suggested that an intervention strategy based on shield immunity could reduce the risk of allowing the higher levels of human interaction needed to support expanded economic activity.

They said the number of people infected by the novel Coronavirus is likely much higher than what has been officially reported, adding that this could aid efforts to utilise the presumed immunity of recovered individuals to protect the

larger community.

Noting an important caveat to this strategy, the scientists said, the duration of immunity to reinfection by SARS-COV-2 remains unknown.

However, based on ear

lier studies they said individuals who survived infections by related viral infections, like

SARS, had persistent antibodies for approximately two years, and those who survived infection to MERS had evidence of immunity for approximately three years.

Determining on a broad scale who has antibodies that may protect them from the novel Coronavirus will require a level of reliable testing not yet available in many parts of the world, the scientists said.

"Our model describes ways in which serological tests used to identify individuals who have been infected by and recovered from COVID19 could help both reduce future transmission and foster increased economic engagement," said Joshua Weitz, study co-author from the Georgia Institute of Technology.

"The idea is to think in advance about how identifying recovered individuals could help serve the collective good, using information collected on neutralising antibodies in new ways," Weitz said.

In the current study, the researchers studied the potential impacts of presumed immunity among recovered persons using a computational model of COVID-19 transmission dynamics.

In a population of 10 million citizens, for example, they said the model predicts that in a worst-case transmission scenario, implementation of an intermediate shielding strategy could help reduce deaths from 71,000 to 58,000.

An enhanced shielding plan, the study said, could cut deaths from 71,000 to 20,000.

Based on the model, the researchers also suggested that shielding could enhance the effects of social distancing strategies that may remain in place once higher levels of economic activity resume.