HomeScienceWhat are the risks of reinfection with Omicron BA.2 variant? WHO explains

What are the risks of reinfection with Omicron BA.2 variant? WHO explains

The World Health Organisation (WHO) declared some finding bringing forth a ray of hope at a time, the world is at the brink of facing what West calls a ‘catastrophic’ war waged by Vladimir Putin-led Russian troops over the east European country, Ukraine. 

Health expert Dr. Maria Van Kerkhove, the Covid-19 Technical Lead at WHO, talked about the reinfection risk of countries that have shown a rather declining trend in their daily Covid-19 cases. 

See what Kerkhove has to say here

WHO on 22 February had announced that based on available data of transmission, severity, reinfection, diagnostics, therapeutics and impacts of vaccines, the group reinforced that the BA.2 sublineage should continue to be considered a variant of concern and that it should remain classified as Omicron. The group emphasized that BA.2 should continue to be monitored as a distinct sublineage of Omicron by public health authorities.

WHO is monitoring countries that showed a steady rise in the epi curve for their Omicron cases during the Covid-19 third wave. This countries also have reported a steady decline in Covid cases. However, WHO is monitoring those countries to conform if there is a risk of re-infection for the Omicron sub-lineage BA.1 and BA.2. 

BA.2 differs from BA.1 in its genetic sequence, including some amino acid differences in the spike protein and other proteins. Studies have shown that BA.2 has a growth advantage over BA.1. Studies are ongoing to understand the reasons for this growth advantage, but initial data suggest that BA.2 appears inherently more transmissible than BA.1, which currently remains the most common Omicron sublineage reported. 

This difference in transmissibility appears to be much smaller than, for example, the difference between BA.1 and Delta. Further, although BA.2 sequences are increasing in proportion relative to other Omicron sublineages (BA.1 and BA.1.1), there is still a reported decline in overall cases globally.

According to Kerkhove, none of the countries have shown an increase in their number of cases at a time when the Covid-19 third wave is on the decline.  She says, this is a ‘good sign’.

Kerkhove also mentioned that there is no difference in the re-infection risk, when sub-lineage BA.1 and BA.2 are compared. 

“If there was an increase, it would mean that re-infection is likely to occur and because we are not seeing that, its a good sign,” Kerkhove said during the press conference. 

WHO is monitoring extremely closely all the countries that had higher numbers of the sub-lineage infections and these countries, according to the Health Agency have only registered a decline in cases. 

WHO official statement said that studies are evaluating the risk of reinfection with BA.2 compared to BA.1. Reinfection with BA.2 following infection with BA.1 has been documented, however, initial data from population-level reinfection studies suggest that infection with BA.1 provides strong protection against reinfection with BA.2, at least for the limited period for which data are available.

“WHO will continue to closely monitor the BA.2 lineage as part of Omicron and requests countries to continue to be vigilant, to monitor and report sequences, as well as to conduct independent and comparative analyses of the different Omicron sublineages,” said the UN health agency. 




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