Currently, we don’t have clear evidence to suggest that the virus is weakening despite a recent claim from a leading Italian virologist that SARS-CoV-2 was "losing its potency". This comment has drawn criticism from the WHO and the scientific community due to this lack of evidence.
So, can viruses change over time? Change is part of a virus’s existence as whenever it infects a new host it replicates itself resulting in not-so-exact copies, which contain mutations in their genetic material. But changes in the virus genome do not guarantee that it is getting ‘weaker’ or that its traits are significantly altered at all. The reason for this is that several genes can control the important traits of the virus (such as its potency or ability to transmit), so for the traits to change, multiple mutations affecting these genes may need to occur.
On the face of it, coronaviruses would have more opportunities to change than others. This is because they have some of the longest genomes among RNA viruses and more genetic material can often mean more opportunities for mutation each time the virus replicates. However, studies into coronaviruses suggest that they are very stable and change only slowly compared to viruses like influenza. This is in part due to a"proofreading" mechanism that corrects errors in coronavirus replication. Disrupting this mechanism represents a target for potential drugs, and may be involved in affecting the potency of the drug remdesivir that has shown promise in accelerating the recovery of hospitalised patients from COVID-19.
Here is the current state of science on a Sparrho pinboard. NB: The pinboard contains research papers that have not been peer-reviewed yet, meaning that they have not gone through the standard scientific validation process yet.
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