Vaccines may require regular updates as Covid develops, say researchers
- Post By :
- Source: PTI
- Date: 27 Mar,2021
A health worker checks the Covishied, a COVID-19 vaccine manufactured by Serum Institute of India, as she prepares to start vaccination against COVID-19 in Kathmandu, Nepal January 27, 2021. (Reuters/Navesh Chitrakar)
Scientists have assessed the course of development of the novel coronavirus and predicted that COVID-19 vaccines currently in use across the world may need regular updates to counter new variants of the virus which are capable of escaping the body’s protective antibodies.
The analysis, published in the journal Virus Evolution, assessed whether, over the long run, the SARS-CoV-2 virus is likely to demonstrate an immune evasion capability on par with that of influenza viruses.
From the research, virologists from Charite — Universitatsmedizin Berlin in Germany studied the genetic development of the four currently known’common cold’ coronaviruses, particularly both longest-known viruses, 229E and OC43.
They traced changes in the spike protein of the these coronaviruses, which enable them to enter host cells, roughly 40 years to the past.
Depending on the analysis, the scientists discovered one feature which was common to both the coronaviruses and the flu virus — all three had a pronounced ladder-like shape in their evolutionary paths.
“An asymmetrical tree of the kind likely results in the repeated replacement of a single circulating virus variant by another which carried a fitness advantage,” explained the study’s first author, Wendy K. Jo.
“It means that these endemic coronaviruses also evade the immune system, exactly like the influenza virus. However, one also has to examine the speed with which this evolutionary adaptation occurs,” she added.
The scientists said the novel coronavirus genome is now anticipated to change at a rate of approximately 10 mutations per 10,000 base molecules annually, meaning the rate at which it evolves is considerably higher than that of the endemic coronaviruses.
“This rapid genetic change in SARS-CoV-2 is reflected in the development of numerous virus variants across the globe,” explained study co-author Jan Felix Drexler.
“This, however, is probably due to the high rates of disease seen during the pandemic. When disease numbers are so high, a virus can grow more quickly,” Drexler added.
Based on the rates of evolution seen in the endemic common cold coronaviruses, the scientists believe SARS-CoV-2 will begin to change more slowly once infections start to die down.
“After a sizable proportion of the global population has developed immunity as a consequence of infection or through vaccination. We anticipate therefore that COVID-19 vaccines will need to be monitored regularly throughout the pandemic and upgraded where necessary,” Drexler explained.
According to the virologists, vaccines are likely to remain effective for longer once the pandemic reaches this stable situation.