Omicron driving spike in new Covid-19 cases in Bangladesh recently and expected to rise in coming days according to health officials.

The Covid-19 positivity rate in Bangladesh has reached the highest-ever 33.37% in last week.

The health authorities recorded 15,440 new infections after testing 46,268 samples across the country. The latest figure took the country's Covid case tally to 17, 62,771, according to the data provided by the Directorate General of Health Services (DGHS).

The U.S. Food and Drug Administration (FDA) issued an emergency use authorization (EUA) for nirmatrelvir tablets and ritonavir tablets (co-packaged for oral use) for the treatment of mild-to-moderate coronavirus disease (COVID-19) in adults and pediatric patients (12 years of age and older weighing at least 40 kilograms) with positive results of direct SARS-CoV-2 testing, and who are at high risk for progression to severe COVID-19, including hospitalization or death.

FDA’s authorization provides a new tool to combat COVID-19 at a crucial time in the pandemic as Omicron variants emerge. 

In a randomized, double-blind, placebo-controlled clinical trial, Nirmatrelvir and Ritonavir significantly reduced the proportion of people with COVID-19 related hospitalization or death from any cause by 88% compared to placebo.

Nirmatrelvir and Ritonavir Effective against Omicron variant?

Multiple studies conducted by Pfizer demonstrating that the in vitro efficacy of nirmatrelvir, the active main protease (M^pro) inhibitor of nirmatrelvir and ritonavir tablets, is maintained against the SARS-CoV-2 variant Omicron.

In the first of these in vitro studies, nirmatrelvir was tested against the M^pro – an enzyme that the coronavirus needs to replicate – from several SARS-CoV-2 variants of concern (VoCs), including Omicron, in a biochemical assay. The results showed in all cases that nirmatrelvir was a potent inhibitor of its target. Nirmatrelvir’s Ki – a measure of its ability to bind to an enzyme – was approximately 1 nanomolar (nM) (or Ki fold change <1) for both the Omicron and the original Washington variant in this assay, indicating its continued ability to prevent in vitro viral replication.

In a second in vitro study conducted, nirmatrelvir was tested against several SARS-CoV-2 VoCs, including Omicron, in an antiviral, cell-based assay. Reduction in viral load was measured through polymerase chain reaction (PCR) analysis, a test designed to detect the virus. Nirmatrelvir’s drug potency showing a concentration that is effective in producing 50% of the maximal response – was 16 nM for the Omicron variant, compared to 38 nM for the USA-WA1/2020 variant, reaffirming its robust in vitro antiviral activity.

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