New variants do not always merit changes in public health response, but keep people alert
The Indian variant, B.1.617 and its family of related coronaviruses have been categorised as a Variant of Concern (VOC) by WHO, a classification which will now prompt greater international scrutiny of those who test positive overseas. While there are several so-called ‘variants of interest’, only three, other than the B.1.617, have been categorised as VOC — the U.K. variant (B.1.1.7), the South Africa variant (B.1.351) and the Brazilian variant (P2). Usually, in countries that detect emergent variants, it is the health authorities there who flag them as potential VOC. To qualify as one, the identified variant must be linked to increased transmission or be associated with more severe disease or found to be evading detection by diagnostic tests. Concerns that the B.1.617 may be playing a role in disease spread in India were expressed by scientists by mid-March. The INSACOG, or the Indian SARS-CoV2 Genomic Consortia, had flagged a variant with two concerning mutations, E484Q and L452R, that separately had been found in other variants elsewhere. INSACOG said they now seemed to appear together on a variant that was linked to a large fraction of cases in Maharashtra and began to be called ‘double mutant’ or even ‘triple mutant’ (as it also had another important mutation, P614R).
In March nearly 20% of the cases out of Maharashtra, which has consistently been among the most afflicted States, were being linked to the variant. However, it was in early April that this variant became formally classified as a lineage, B.1.617. It was only after the U.K.’s labelling it as a VOC that it was called so by health authorities in India. In fact, unlike the United States’s CDC or Public Health England, India still does not have a classification criterion for labelling viruses as variants of interest, or concern. Classifying variants is not just a matter of mere academic interest. Based on the prevalence, some variants may go on to become the dominant strain in a region or multiple geographies. It then becomes the responsibility of vaccine companies to check whether their vaccines continue to be effective. Such studies have already begun in India, but while laboratory studies show that vaccines continue to be effective, some of the emerging variants do seem to be better at evading antibodies. Along with monitoring reinfections and cases of breakthrough infections (testing positive after being double inoculated), flagging variants must be seen as a crucial health response. Detecting newer variants does not always merit radical changes in public health response — such as masking up — but they go a long way in reminding people to continue being alert, viewing vaccines as an important defence but not a magic pill, and keeping health authorities on their toes.