Kerala is reeling under the surge of new cases in the second wave of COVID-19 and the intense and fast pace of disease transmission has taken everyone by surprise.
Public health experts in the State now believe that given the similarities in the manner in which COVID-19 cases, hospitalisations and deaths have been soaring in Kerala as it is in Maharashtra, there is a high likelihood that the “double mutant variant” or the SARS-CoV2 lineage B.1.617 found predominantly in that State, could be driving disease transmission here too.
“People gathering in huge numbers, in blatant violation of all COVID safety norms during the month-long election campaigning is one of the primary reasons for the rise in cases now. But the pace in disease transmission is what makes us fear that an additional factor may be at play here. However, we need molecular data on the current virus samples from the State to reach a conclusion,” a public health expert and member of the State’s expert committee on COVID-19, said.
Genomic sequencing
Genomic sequencing of virus samples from Kerala during December-February had found the presence of the variant N440K in 11 districts in Kerala. But till date there has been no epidemiological link to connect this variant to the disease transmission pattern here.
Kerala’s COVID graph had been on an extended plateau after it first peaked in October but since February, the graph had been on a decline. On January 30, the State had 71,469 active cases and this was rapidly brought down to 23,883 by March 23.
But since then, cases have soared and in the next 22 days, Kerala added 33,362 cases to its active case pool.
Exponential increase
In Maharashtra, where cases are on an exponential increase, 61% virus samples from various cities have been found to be the B.1.617 variant. On Thursday, the Union Government said that the same variant had been found in Delhi, West Bengal, Gujarat, Karnataka and Madhya Pradesh too and that it definitely had a role in the rapid rise in COVID cases in these States.
The B.1.617 lineage is defined by two spike protein mutations, E484Q and L452R, which are involved in immune escape (which renders the virus capable of escaping the immune system’s response) as well as increased infectivity.
According to a pre-print in biorxiv.org, L452R can reinforce the affinity to viral receptor ACE2, increase viral replication and escape even cellular (T cell) immunity.
Kerala facilities
Though virus samples for genomic sequencing have been sent to the National Institute of Virology and Institute of Genomics and Integrative Biology, New Delhi, the gravity of the situation in Kerala has encouraged the expert committee to recommend that the State’s own scientific institutions can be utilised for this work.
“Current local samples from Kozhikode will be sent to the multidisciplinary research lab at Government Medical College Hospital, which can amplify the virus’ spike protein gene alone and check for mutations. The sooner we have information about what is happening on the ground, the faster we can act,” he said.
Public health experts point out that if B.1.617 variant is indeed playing a role in disease transmission in the State, then it is quite likely that the current wave will be much more prolonged than the first wave.
Though vaccination is the only tool available to fight the virus, mass vaccination in the middle of a raging pandemic can never outpace the virus. A rapid spread could result in hospitals getting overwhelmed, pushing up mortality.
Published - April 16, 2021 12:40 am IST
