Since the emergence of the COVID variation Omicron in late 2021, it has swiftly mutated into numerous subvariants. One subvariant, BF.7, was recently discovered as the predominant variant circulating in Beijing, and is contributing to a larger increase in COVID infections in China.
However, what exactly is this new variation, and should we be concerned? Although reports from China regarding the characteristics of this variant are worrisome, it does not appear to be expanding rapidly elsewhere in the world. Here are the known facts.
BF.7, which is an abbreviation of BA.5.2.1.7, is a sublineage of the Omicron variation BA.5.
According to reports from China, BF.7 has the highest infection capacity among the Omicron subvariants in the country, as it transmits more rapidly than other variants, has a shorter incubation period, and has a greater capacity to infect individuals who have had a previous COVID infection, been vaccinated, or both.
In context, it is believed that BF.7 has a R0, or basic reproduction number, between 10 and 18.6. This indicates that one infected individual will spread the virus to an average of 10 to 18.6 other individuals. According to studies, Omicron has an average R0 of 5.08.
It is believed that the high transmission rate of BF.7, coupled with the possibility of undetected spread due to the large number of asymptomatic carriers, is making it extremely difficult to control the epidemic in China.
The symptoms of a BF.7 infection are comparable to those of other Omicron subvariants, specifically upper respiratory symptoms. Patients may experience, among other symptoms, fever, cough, sore throat, runny nose, and weariness. Some individuals may also develop gastrointestinal problems such as vomiting and diarrhea.
BF.7 may induce more severe sickness in individuals with compromised immune systems.
BF.7 has mutations
As Omicron has developed, new subvariants have emerged that are better able to evade immunity from vaccination or previous infection. BF.7 is identical.
BF.7 possesses a particular mutation, R346T, in the SARS-CoV-2 spike protein (a protein on the surface of the virus that allows it to attach to and infect our cells). This mutation, which is also present in the “parent” form of BF.7, BA.5, has been related to an increase in the virus’ ability to evade neutralizing antibodies produced by vaccinations or past infection.
A recent study assessed the neutralization of BF.7 in sera (a blood component that should contain antibodies) from triple-vaccinated healthcare workers and patients infected during the Omicron BA.1 and BA.5 pandemic waves. The R346T mutation partially contributed to BF.7’s neutralizing resistance.
BF.7 across the globe
BF.7 has also been found in India, the United States, the United Kingdom, and several European nations including Belgium, Germany, France, and Denmark.
Despite BF.7’s immune-evasion properties and alarming growth indicators in China, the variety appears to be relatively stable elsewhere. As of December 10, it was projected to account for 5.7% of infections in the United States, down from 6.6% the week prior.
In an October technical briefing, the UK Health Security Agency identified BF.7 as one of the most worrisome variants in terms of both growth and neutralization data (it accounted for over 7% of cases at the time), but the most recent briefing indicates that BF.7 has been de-escalated due to decreased incidence and low growth rates in the UK.
We do not know exactly why the situation in China appears different. The high R0 of BF.7 may be partially attributable to a low degree of immunity in the Chinese population due to past infection and potentially vaccination as well. Since the data from China is based on reports and not yet peer-reviewed proof, we must be wary.
An developing virus
Since the appearance of SARS-CoV-2 three years ago, the virus has continued to mutate, accruing unexpectedly rapid genomic alterations.
Concerning is the introduction of BF.7 and other new variations. However, immunization remains the most effective method for combating COVID. And the recent clearance by the United Kingdom’s pharmaceuticals authority of bivalent boosters that target both Omicron and the original strain of SARS-CoV-2 is extremely encouraging.
»What you should know about the Omicron COVID version BF.7«