New analysis shows that SARS-CoV-2 mutations are not uncommon in subsequent transmissions

A study of the diversity of the SARS-CoV-2 genome in over 1,000 people in the United Kingdom suggests that, in the event of viral mutations, they can be transmitted in some cases but rarely continue. with subsequent referrals.

“Our observations indicate that vaccine and therapeutic-escape mutations appear to be very rare,” the authors say, “at least during early disease when viral loads are high.” However. , because mutations that can be avoided by medications such as antibodies have been identified, including in higher viral load samples, the authors encourage continuous monitoring and surveillance, to especially since there are vaccines and medications that “stress” viruses to make them more widely adapted. Most analyzes of mutations in SARS-CoV-2 to date have focused on mutations observed in individuals that represent the major mutations.

However, new mutations are emerging in infected individuals, too, and the full underlying diversity of viruses in human hosts is known – how often they appear, and at least they are transmitted – important for understanding viral change and transmission patterns. To better characterize diversity in single human hosts, Katrina Lythgoe and colleagues used an RNA sequencing method to analyze 1,390 SARS-CoV-2 genomes from 1,313 heavily sampled nasopharyngeal swabs. -some of typical UK patients who became ill between March and June 2020 (the first global wave of diseases).

The authors observed only one or two variations in the majority of individuals, but a few patients had several differences. Most of these were lost at the time of transmission, although a small number began continuous and wider transmission. Also, there were very few cases of transmission of viruses between homes in the genomes studied. These findings suggest that during early infection, mutations that increase the chances of the virus getting away from cures are rare.

Nevertheless, the authors identified changes that could benefit the virus, including high viral load samples. This indicates that naturally occurring variables would have a chance to spread as the pressure of population selection from vaccine distribution increases. The findings reinforce the need for ongoing scrutiny, they say.