BF.7 Omicron Subvariant: Understanding Symptoms and Severity

Understanding Symptoms and Severity of the BF.7 Omicron Subvariant

The COVID-19 pandemic continues to evolve as new variants of the SARS-CoV-2 virus emerge. One subtype gaining traction globally is the BF.7 omicron subvariant.

BF.7 descends from earlier BA.5 lineages of omicron but contains key mutations that may impart immunoevasion and increased transmissibility. As BF.7 cases rise, it is critical to understand its potential symptoms and severity compared to past variants.

This article provides an overview of the current research on BF.7, including its prevalence, contagiousness, vaccine evasion, typical symptoms, risk factors, and how its severity compares to previous COVID strains based on early data.

Origins and Prevalence of BF.7

The BF.7 omicron subvariant first emerged in China in late October 2022. It quickly spread throughout mainland China before making its way overseas.

In the U.S., BF.7 now accounts for an estimated 5.7% of COVID cases as of late November 2022. Rates are even higher in parts of Asia and Europe. The UK has seen BF.7 grow to 13% of infections.

Experts expect BF.7 will continue gaining ground globally through the winter, possibly overtaking BQ.1.1 to become the dominant variant.

Increased Immune Evasion

A key factor driving the spread of BF.7 is its apparent ability to evade immunity from vaccination and previous infection. This immune evasion is linked to specific mutations:

• R346T mutation in the spike protein helps escape antibodies
• F486P mutation also improves antibody evasion
• Other changes enhance ACE2 receptor binding

According to early lab studies, these mutations make BF.7 the most effective omicron variant yet at avoiding neutralizing antibodies. More research is still needed on real-world immune evasion effects.

Is BF.7 More Transmissible Than Other Variants?

Along with improved immune evasion, preliminary evidence indicates BF.7 spreads faster than earlier omicron variants such as BA.5.

In China, BF.7 outpaced other variants by 13% in transmissibility based on epidemiological modeling. The R346T mutation again appears key, as it likely helps the virus better bind to host cells.

However, some experts believe higher transmissibility is primarily linked to evasion of population immunity rather than changes to viral biology. More data is required to confirm if BF.7 has an inherent transmission advantage.

BF.7 Infection Symptoms

Understanding the symptoms of BF.7 can help in detecting potential infection and seeking proper diagnosis and care if needed. According to initial reports, symptoms appear consistent with earlier omicron variants.

Most Common Symptoms

Data on BF.7 infections in China found the most prevalent symptoms were:

• Cough
• Nasal congestion
• Sore throat
• Fatigue

Other commonly reported symptoms include:

• Headaches
• Muscle aches
• Loss of smell/taste
• Fever

Notably, fewer patients reported fever compared to earlier COVID variants. Loss of smell and taste also appears less prominent.

Gastrointestinal Symptoms

Previous omicron variants caused more upper respiratory symptoms than fevers or gastrointestinal issues. However, BF.7 may revert back to some hallmark COVID-19 gastrointestinal symptoms like:

• Nausea/vomiting
• Diarrhea
• Abdominal pain

More evidence is needed to confirm higher rates of digestive issues with BF.7. But anecdotal reports from China and Singapore noted increased vomiting and diarrhea in infected individuals.

Atypical Symptoms

While most BF.7 cases appear typical, some unusual symptoms have been reported in Chinese health bulletins:

• Hemoptysis - coughing up blood
• Conjunctival congestion - red eyes
• Rashes

These atypical symptoms were relatively rare. Their connection to BF.7 remains unconfirmed. But it is important to note COVID can manifest differently across individuals, particularly with new variants.

BF.7 Infection Severity and Risks

A critical question surrounding new variants like BF.7 is whether they cause more severe illness compared to past strains. Currently available data on disease severity is limited but offers some preliminary insights.

Hospitalization Rates

Early evidence from China indicates hospitalization rates for BF.7 infections are lower than for past omicron waves. In Beijing, only 2.3% of BF.7 cases required hospitalization compared to 18.3% with BA.5.2.

Lower severity could be attributed to higher population immunity in China after its recent infection surge. But the data tentatively suggests BF.7 may follow omicron trends of causing less severe outcomes on average.

Vulnerable Populations Remain at Risk

Despite potentially lower severity overall, BF.7 still poses significant risks for vulnerable groups. In particular:

• Older adults
• Unvaccinated individuals
• People with underlying conditions

These demographics are more prone to severe disease with any COVID variant. Early indications are that elderly mortality rates remain high in Chinas BF.7 wave, consistent with previous omicron surges.

Reinfection Risks

The mutations allowing BF.7 to evade antibodies also make reinfection more likely. Getting COVID multiple times raises risks of:

• Long COVID complications
• Organ damage
• Blood clots
• Cognitive decline

Reinfections appear capable of causing severe illness again even in generally healthy people. Avoiding repeat COVID infections remains important amid new antibody-evasive strains.

Symptoms in Vaccinated People

Current COVID vaccines continue providing protection against severe disease and death, even from newer variants. But their effectiveness against infection has waned.

Most vaccinated people with breakthrough BF.7 infections will experience mild cold/flu symptoms for a few days. But illness duration and severity can be higher in those who are older or immunocompromised.

Prevention and Treatment Considerations

As BF.7 spreads globally this winter, people want to know how best to protect themselves and treat infections if they occur. Key prevention and treatment considerations include:

Get Updated Boosters

COVID vaccines adjusted for omicron remain the best protection against emerging subvariants like BF.7. Ensure you are up-to-date on the latest recommended boosters to increase antibody levels.

Use Quality Masks

Well-fitting, high-filtration masks (e.g. N95, KN95) help slow airborne transmission of COVID in indoor spaces. Mask diligently in crowded public settings.

Improve Ventilation

Proper ventilation reduces concentration of viral particles indoors. Open windows, upgrade HVAC filters, and consider portable air cleaners for high-risk spaces.

Treat Early With Antivirals

Oral antivirals like Paxlovid are highly effective at reducing COVID severity if taken shortly after symptom onset. At-risk individuals should seek rapid treatment.

Use Over-the-Counter Medications

For mild infections, OTC medications can relieve symptoms. Try acetaminophen for fever and pains or decongestants for nasal congestion.

Stay Hydrated and Rested

Drink fluids, use humidifiers, rest as much as possible, and stay nourished. Listen to your body and don't overexert while recovering.

BF.7 does not appear to have escaped the protection offered by updated boosters. But masking, improving ventilation, and early therapeutics provide added security amid uncertain variants.

Global Outlook for BF.7 This Winter

Looking ahead to the coming months, here are some projections for the spread and impact of the BF.7 variant:

Continued Growth Expected

Given its current trajectory, BF.7 will likely keep rising as a share of COVID infections through the winter season in the Northern Hemisphere. It could overtake BQ.1.1 as the new dominant variant.

Potential Winter Surges

More BF.7 circulation could fuel fresh surges and waves around the world this winter. Population immunity has waned since summer. Holiday gatherings may also facilitate new spread.

Vaccines Will Provide Ongoing Protection

While the effectiveness of original COVID vaccines has diminished, updated omicron boosters should continue providing protection against severe outcomes with BF.7 based on current evidence.

Treatment Options Remain Effective

There are no indications BF.7 will evade current treatments. Antivirals, antibody drugs, and other therapeutics are expected to remain potent options for high-risk patients.

Long-Term Outlook Uncertain

The full implications of BF.7s mutations remain uncertain. It could follow other omicron strains as a relatively mild threat. But its ability to reinfect and seasonal factors make predictions difficult.

Continued genomic surveillance, tracking of emerging real-world data, and updating interventions accordingly will be key responding to new variants like BF.7.

Disclaimer: This article is for informational purposes only and does not constitute medical advice. Always consult with a healthcare professional before starting any new treatment regimen.