People with asymptomatic Covid-19 are less infectious than those with symptoms

by time news

R. I.

Madrid

Updated:05/26/2022 8:00 p.m.

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People with asymptomatic SARS-CoV-2 infection are less infectious than those with symptomatic infection and, therefore, contrary to what has been suggested, are less responsible for the spread of Covid-19 than symptomatic people

Seen by a review of 130 different studies published in PLoS Medicine which reveals that the proportion of asymptomatic infections is 50% or less in most studies

According to studies published up to July 2021, the majority of SARS-CoV-2 infections were not asymptomatic and, furthermore, they were less infectious than symptomatic ones.

The debate about the level and risks of asymptomatic SARS-CoV-2 infections continues, with much research ongoing.

Studies evaluating people at a single time point may overestimate the proportion of true asymptomatic infections, as those who subsequently develop symptoms are incorrectly classified as asymptomatic rather than presymptomatic. However, other studies may underestimate asymptomatic infections with research designs that are more likely to include symptomatic participants.

The new document coordinated by Diana Buitrago-Garciafrom the University of Bern, Switzerland, is an update of a living (i.e. regularly updated) systematic review first published in April 2020, including additional and more recent studies up to July 2021.

We included 130 studies, with data on 28,426 people with SARS-CoV-2 in 42 countries, including 11,923 people defined as having asymptomatic infection. Due to the extreme variability between the included studies, the meta-analysis did not calculate a single estimate of the rate of asymptomatic infection, but did estimate the interquartile range to be 14-50% of asymptomatic infections.

The researchers found that the rate of secondary attacks was about two-thirds lower in people without symptoms than in those with symptoms.

In addition, the researchers found that the rate of secondary attacks – a measure of the risk of SARS-CoV-2 transmission – was about two-thirds lower in people without symptoms than in those with symptoms.

“If both the proportion and transmissibility of asymptomatic infection are relatively low, people with asymptomatic SARS-CoV-2 infection should account for a smaller proportion of global transmission than presymptomatic individuals,” the authors state, while point out that “when the levels of community transmission of SARS-CoV-2 are high, it is necessary to maintain physical distancing measures and the use of masks to avoid transmission through close contact with people with asymptomatic and presymptomatic infection.”

the co-author Nicola Low He adds that “the true proportion of asymptomatic SARS-CoV-2 infection is not yet known, and it would be misleading to rely on a single figure because the 130 studies we reviewed were very different. However, people with a truly asymptomatic infection are less infectious than those with a symptomatic infection.”

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