China has recently reported an explosive surge of Covid-19 cases and deaths. BF.7, a sub-lineage of the Omicron variant, is believed to be responsible for this outbreak, which has gained considerable global attention. Several countries have stepped up precaution measures at ports of entry.

BF.7, also known as BA.5.2.17, is not a new virus or the one that first appeared in China; rather, it has been circulating in the United States and Europe since a couple of months ago. There has been no unusual increase in hospitalisations and deaths due to the virus. Likewise, in India, BF.7 was first detected in July last year. No new Covid-19 wave has been seen since then. A few days ago, the Government of Nepal released sequencing data for the SARS-CoV-2 virus detected in various parts of the country. Surprisingly, 17 sub-lineages, including the rapidly spreading virus “XBB” of Omicron, have been found circulating. Despite the presence of many Omicron sub-lineages and the absence of safety measures, Nepal did not observe any new Covid-19 wave even after big festivals such as Dashain, Tihar, Chhat and the parliamentary election that followed. Safety measures are no longer mandatory in public places in Nepal and other countries.

It will be interesting to see the understanding discrepancy between China and the rest of the countries regarding the sudden rise and severe disease of BF.7 sub-lineage of Omicron, but it has yet to be unveiled. Omicron is considered less lethal than its earlier Delta variant. It was somewhat surprising that during the third Omicron wave, almost all deceased patients were found to be elderly with underlying conditions and unvaccinated or partially vaccinated (a complete two-dose primary series). Similarly, during the Omicron variant surge in Hong Kong, most deaths occurred in people over 60 years; of those, 70 percent were unvaccinated. These observations clearly show that the Omicron variant can be lethal, particularly to the elderly, the unvaccinated and those with medical conditions. So it can be assumed that unvaccinated elderly may have been suffering from BF.7 in China, where vaccination coverage among senior citizens, especially those 80 or above, is low.

The Ministry of Health and Population has said BF.7 is yet to be detected in Nepal. However, amid the ongoing BF.7 crisis in China, the possible introduction of this virus has created fear among people. In Nepal, the Omicron variant had increased significantly during the winter season last year. Omicron variants display symptoms similar to influenza or common cold viruses. Since the winter season has arrived, influenza-like illnesses have increased significantly over the last few days. Sooner or later, BF.7 will arrive in Nepal, exhibiting symptoms similar to those of the influenza virus, necessitating testing facilities to identify BF.7 and distinguish it from the influenza virus because the two illnesses are caused by different viruses and are treated accordingly.

Several studies have shown that booster shots can effectively prevent severe symptoms and deaths caused by sub-lineages of Omicron. Therefore, the concerned government body and experts have urged the public to get a booster dose. As a matter of fact, nowadays, people are interested in getting a booster dose. Unfortunately, vaccines for booster shots are not readily available, and people are unaware of the vaccination centres. Repeated infections with various Omicron sub-lineages may develop natural antibodies and play a key role in preventing complications and deaths from Covid-19. For instance, 17 sub-lineages of Omicron found circulating in Nepal may have developed antibodies against Covid-19 that may protect them from severe disease even if the BF.7 is introduced in the near future. In other words, it is reasonable to assume that BF.7 may not cause a fresh wave of a severe form of Covid-19 in Nepal, as it happened in China.

It seems plausible that BF.7 has had additional/new mutations in their proteins or been co-circulating with multiple existing sub-lineages of Omicron, thereby contributing to the current outbreak with increased severity of disease in China. Also, other respiratory viral diseases, such as influenza and respiratory syncytial virus (RSV), co-circulating with BF.7, dubbed “tridemic” or “tripledemic”, might have resulted in the current situation in China. Usually, in most cases, once/if the coronavirus is detected, further testing is not done. In fact, flu activities across the globe (including in Nepal) have increased markedly in recent weeks. However, further evidence is needed to understand whether solely BF.7 or co-circulating with other respiratory viruses or even unknown viruses collectively are responsible for the current deadly outbreak in China.

BF.7 is less likely to create a China-like situation in Nepal. However, Omicron sub-lineages are known to be capable of causing severe illnesses, hospitalisations and deaths in unvaccinated elderly with medical conditions. Thus, the government must ramp up booster vaccinations for vulnerable groups because SARS-CoV-2 is continuing to evolve, creating new viruses that may surge unexpectedly anywhere, anytime.