A new variant of SARS-CoV-2 circulating in South Africa has been classified as variant of concern by the World Health Organization (WHO).
The variant has been named as Omicron, after the Greek letter. The viruses belong to a lineage named B.1.1.529.
Early studies have shown that this variant has increased chances of transmissibility as compared to the Delta variant. The effectiveness of existing vaccines is also questioned.
The emergence of new mutants is quite common during pandemics. The health authorities are on constant vigil to identify new strains.
The new strain, indicated as B.1.1.529, has multiple mutations in its spike proteins. This makes the strain highly infectious.
After the emergence of B.1.1.529 strain, the cases in South Africa have increased four fold in the last two weeks.
Mutations in the strain
The strain has about 30 mutations across the spike proteins. This is responsible for making the virus entry into human cells easier.
All the mutations have not been studied in details to understand its significance. It will take some time to study the possible effects.
Mutation known as H655Y + N679K + P681H, plays a major role in efficient cell entry, indicating enhanced transmissibility.
A depletion known as nsp6 has also occurred, which is similar to one in Alpha, Beta. Lambda and Delta variant. This could help in avoiding immunity and enhance transmissibility.
The variant also has a mutation, R203K+G204R, which is associated with increased infectivity in population.
There are no unusual symptoms associated with this variant. Some people are asymptomatic, as with other infectious variants such as Delta.
Studies are being conducted in laboratory settings to determine if the strain is associated with disease severity or it may affect performance of therapeutic medicines.