Given the current available data, it is likely that Omicron will outpace the Delta variant of covid-19 where community transmission occurs, a World Health Organisation update said today.

 

"Based on current limited evidence Omicron appears to have a growth advantage over Delta. It is spreading faster than the Delta variant in South Africa where Delta circulation was low, but also appears to spread more quickly than the Delta variant in other countries where the incidence of Delta is high, such as in the United Kingdom," the update said. 

 

There are still limited data on the clinical severity of Omicron, it said.

 

"While preliminary findings from South Africa suggest it may be less severe than Delta, and all cases reported in the EU/EEA to date have been mild or asymptomatic, it remains unclear to what extent Omicron may be inherently less virulent. More data are needed to understand the severity profile," it added.

 

There are limited available data, and no peer-reviewed evidence, on vaccine efficacy or effectiveness to date for Omicron, the update said.

 

"Preliminary evidence, and the considerably altered antigenic profile of the Omicron spike protein, suggests a reduction in vaccine efficacy against infection and transmission associated with Omicron. There is some preliminary evidence that the incidence of reinfection has increased in South Africa, which may be associated with humoral (antibody-mediated) immune evasion. In addition, preliminary evidence from a few studies of limited sample size have shown that sera obtained from vaccinated and previously infected individuals had lower neutralization activity (the size of the reduction ranges considerably) than with any other circulating VOCs of SARS-CoV-2 and the ancestral strain."

 

Therapeutic interventions for the management of patients with severe or critical Covid-19 associated with the Omicron variant that target host responses (such as corticosteroids, and interleukin 6 receptor blockers and prophylaxis with anticoagulation) are expected to remain effective.  However, monoclonal antibodies will need to be tested individually, for their antigen binding and virus neutralization and these studies should be prioritised, it recommended. - TradeArabia News Service