In early December 2022, China abandoned its zero-Covid policy and reports of an increase in cases, hospitalizations, and deaths followed. However, the country has not been transparent with its data, leading the World Health Organization (WHO) to state that the data published by China “underrepresent the true impact of the disease.”
The WHO conducted a meeting with Chinese scientists and subsequently confirmed that the local cases in China were caused by two sub-variants of SARS-CoV-2’s Omicron variant: BF.7 and BA.5.2.
Omicron Variant and Its Sub-Variants:
The Omicron variant of SARS-CoV-2 is one of several variants of concern (VOCs) that have emerged since the start of the pandemic. It was first identified in South Africa in November 2021 and has since spread to numerous countries around the world. The Omicron variant is characterized by a number of mutations that may affect its transmissibility, severity, and immune evasion.
There are several sub-variants of the Omicron variant, including BF.7 and BA.5.2. The BA.5.2 sub-variant was first detected in June 2021, but it didn’t gain traction until July 2022, when it spread rapidly and replaced dominant variants in several countries. It has a low risk of severe outcomes.
The BF.7 variant is a sub-lineage of the BA.5 sub-lineage of Omicron and is characterized by a high neutralization resistance, meaning it is more efficient at evading immune response from natural infection or immunization.
Increase in Cases in China:
The WHO’s technical advisory group on virus evolution (TAG-VE) analyzed two datasets in order to confirm that the BF.7 and BA.5.2 sub-variants were driving the increase in cases in China.
The first dataset consisted of 2,000 genomes sequenced by China from December 1, 2022 onward and shared with the WHO. The second dataset consisted of 773 sequences from mainland China available on the global database GISAID.
The analysis showed that these two variants accounted for 97.5% of the 2,000 genomes of local infections shared by China. Additionally, 95% of locally acquired samples from the 773 genome sequences on GISAID were lineages of BF.7 and BA.5.2.
Experts believe that the surge in cases in China is due to the population being largely immune-na’ve to Omicron sub-variants due to the country’s strict zero-Covid policy. This has allowed the BF.7 and BA.5.2 variants to spread more easily. Other countries that have identified the BF.7 variant, such as the US and UK, have not reported a significant increase in cases or hospitalizations.
Presence of BF.7 and BA.5.2 in India:
Both the BF.7 and BA.5.2 sub-variants have been reported in India. The BA.5.2 variant was first identified in May 2022 and spread in the country over the following months. In December 2022, BA.5 sub-lineages were found in 6.1% of the genomes sequenced by India’s SARS-CoV-2 genome sequencing consortium INSACOG. As for BF.7, the first case was reported in September and then another case in November 2022.
However, the variant did not spread widely in the country at the time. After the surge in cases in China, more cases of BF.7 were detected in India, with 2.4% of samples sequenced in December 2022 containing the variant, according to INSACOG. One case of BF.7 was also detected in an international passenger randomly tested in India on December 24.
It is important for India to closely monitor the spread of these variants, as well as any potential new variants that may emerge. The country has already implemented measures such as random testing of international passengers and genome sequencing of a certain percentage of positive cases. In addition, India has ramped up its vaccination efforts, with over 70 million doses administered as of January 8, 2023.
The BF.7 and BA.5.2 sub-variants of the Omicron variant of SARS-CoV-2 have been identified as the main drivers of the increase in cases in China. Both variants have also been reported in India, although their spread in the country has been limited so far. It is crucial for India to continue monitoring the situation and implementing measures such as genome sequencing and vaccination to prevent the spread of these variants.