pandemic still not over!? virus is still evolving!

pandemic still not over!? virus is still evolving!

“Living with the virus is proving much harder than the early vaccine success suggested: this fight is far from over.”

The last large wave in India was caused by the omicron variant, particularly its BA.2 sub-variant. According to computational biologist Raj Rajnarayanan, of Arkansas State University, the most prevalent sub-variant in India as of June 24 was BA.2.38, which accounted for 36% of all sequenced isolates). It was closely followed by BA.2 (34%), BA.5 – the most worrisome of the omicrons sub-variants (10%) and BA.4 (1-2%).

The BA.5 sub-variant has the most transmissibility and immune escape potential of any variant since the COVID-19 pandemic began.

Some researchers have estimated that BA.5 is around 36% more infectious than BA.2 – the ‘original’ omicron variant. 

 Cell culture experiments revealed that BA.4 and BA.5 replicate more efficiently in human alveolar epithelial cells than BA.2, and that BA.5 fuses better with host cells than does BA.2.

the BA.5 sub-variant is expected to be able to cause more severe illness than prior sub-variants of omicron.

However, the omicron sub-variants in general have also been causing fewer deaths and hospitalizations than their older cousins – a sign that growing population immunity could temper the immediate consequences of news waves.

The BA.2.75 sub-variant has some alarming mutations in the key spike protein.

Thus far, in India, nine states have reported samples with BA.2.75.

there is a chance that BA.2.75 could induce milder disease than previous omicron-variant lineages.

BA.5 and its emerging sub-lineages – i.e. BA.5.1, BA.5.2, etc. – have been able to evade both natural and vaccine-induced immunity. Similarly, most of our monoclonal/polyclonal antibodies may fail to work. So we may see ourselves revert to a situation worse than when the ‘original’ novel coronavirus first emerged.

the immunity gained through past infections by BA.1, BA.2, and BA.2.12.1 or vaccination may not protect against BA.4 and BA.5.

There is a silver lining, however. The protein subunit vaccine Novavax, which Serum India’s Institute is producing under the brand name ‘Covovax’, has been shown to protect to a good degree even against the BA.5 sub-variant. Its booster dose form was also found to accord a substantial level of protection against all variants.

The Government of India must focus on this facet of the Covovax vaccine and prioritize its use in the national booster vaccination drive in all age groups.