LONDON (Reuters) – The coronavirus that causes COVID-19 mutates as it spreads worldwide in a pandemic, but none of the currently documented mutations make it possible to spread as quickly as possible, scientists said on Wednesday.
In a study using a global virus genome database of 46,723 people with COVID-19 from 99 countries, researchers identified more than 12,700 mutations or changes in the SARS-CoV-2 virus.
“Fortunately, we found that none of these mutations made COVID-19 spread faster,” said Lucy van Dorp, a professor at the Institute of Genetics at University College London and one of the study’s lead researchers.
She added, however, “We need to stay vigilant and continue to monitor new mutations, especially when vaccines are expanding.”
Viruses are known to mutate constantly, and some – such as influenza viruses – change more often than others.
Most mutations are neutral, but some may be either beneficial or harmful to the virus, and some may make vaccines against them less effective. When viruses change like this, vaccines against them need to be adjusted regularly to make sure they hit the right target.
With the SARS-CoV-2 virus, the first vaccines that show efficacy against the disease they cause may receive regulatory approval and be used to immunize humans before the end of the year.
Francois Balu, a UCL professor who also worked on the study, said his findings posed no threat to the effectiveness of COVID-19 vaccines for the time being, but warned that the immediate introduction of vaccines could put new selective pressure on the virus to mutate to try to avoid the human immune system.
“The news on the vaccine front looks great,” he said. “The virus could well acquire mutations to escape vaccines in the future, but we are confident that we will be able to label them immediately, allowing for timely vaccine updates if needed.”
The mutation study, whose preliminary findings were originally published in May as a pre-print before being reviewed by other scientists, was published in full on Wednesday in the peer-reviewed journal Nature Communications.
The research team from the British University UCL and Oxford and the French Cirad and the University de la Reunion, analyzed the virus genomes of 46,723 people with COVID-19 from 99 countries, collected by the end of July 2020.
Among the more than 12,706 identified mutations, about 398 appear to have occurred continuously and independently, the researchers said.
Of these, scientists focused on 185 mutations that they found occurred at least three times independently during the pandemic.
Researchers have found no evidence that any of the common mutations increase the transmission of the virus. Instead, they said, the most common mutations are neutral to the virus.
Report by Kate Keland, edited by Nick McPhee