What’s Different about Omicron Variants BA.4 and BA.5?

By Dr. Stephanie Paulmeno, DNP, RN, NHA, CPH, CCM, CDP Public Health Education Specialist/Greenwich Department of Health

What’s different? Well, Omicron BA.4 and BA.5 are the most highly contagious subvariants of COVID-19 that we’ve seen yet.

The mutations that created the Omicron BA.4 and BA.5 subvariants altered their spike protein. This precipitated two important changes. It made them more proficient in invading our cells, which is what causes viral infection in all their forms. Importantly, it also made them more resistant to the disease-fighting antibodies that we acquire through vaccinations and when we become COVID-19 infected.

Those two factors have contributed to the swift rise in COVID-19 infections that we are now seeing. Since first being identified in the U.S. (early in July, 2022) Omicron subvariants BA.4 and BA.5 have rapidly become the dominant COVID-19 strains across the country. According to CDC data (7/13/22), BA.5, which is the more contagious of the two, represented 65% of all U.S. COVID-19 cases (Katella, 2022), and together Omicron subvariants BA.4 and BA.5 are now responsible for 80% of the country’s COVID-19 cases (Wendler, 2022). That is in less than 2-weeks from their emergence in the U.S.! Connecticut has already logged 18,176 Omicron cases, and we now have 293 people hospitalized in Connecticut with laboratory-confirmed COVID-19 (Lamont, 7/14/22)

Both Omicron subvariants BA.4 and BA.5 trigger milder UPPER respiratory infections (coughs, congestion, runny noses, sore or scratchy throats, and headaches) as opposed to the original COVID-19 infections that took the lives of so many. The symptoms of the LOWER respiratory infections seen then included such diagnoses as bronchitis and pneumonia with all their breathing difficulties and air-exchange problems, which precipitated many of the earlier hospitalizations, ICU admissions, intubations, and deaths that we saw. On July 14, 2022, Connecticut had an increase of 29 people hospitalized with COVID over the last 7 days, and an increase of 30 deaths from COVID-19 over that same 7-day period. Greenwich and Stamford in our area are again designated as being in the highest transmission zone (Lamont, 7-14-22). This rise in numbers, hospitalizations, and deaths should spark action on our part to get vaccinated, to wear masks when indoors with groups of people, to be mindful of social separation, and to be conscientious about handwashing, respiratory etiquette, and COVID-19 testing. Only we can help ourselves to overcome these alarming trends, yet I see little that we as individuals are doing. Sadly, I rarely see a mask on in Greenwich now, no matter where I go. But let’s look more closely at the contributing factors to the rapid spread of the Omicron subvariant s BA.4 and BA.5. There is science behind the fact that masks (Sypsa, 2021) and social separation (Matrajt and Leung, 2020) can and do stop or slow the spread of a respiratory or airborne viruses.

It is fortunate for us that despite being so much more transmissible from person to person, Omicron subvariants BA.4 and BA.5 do NOT appear to make those who become infected any more ill than had the earlier Omicron versions and certainly less ill than the Delta and the other original COVID-19 versions, which, by the way, are still continuing to also circulate.

Omicron BA.4 and BA.5 are NOT more lethal (deadly) mutations than any of these earlier versions. It’s just that with so many more people becoming infected now, proportionally more people are requiring hospitalization and more deaths are again being seen.

It is the increasing numbers of infected people that is responsible for creating this rise in hospitalizations and deaths, not that people are becoming more seriously ill (CDC, 2022) (Croft, 2022) (Wendler, 2022). Regardless, why would we as individuals not want to do all we can to protect us and our loved ones from 6-months old and up from falling victim to a largely vaccine-preventable and infection control-preventable disease? We all have the tools (vaccines, masks, tests) and we know what to do to protect ourselves and our loved ones.

The antibody-resistance we see with both of these subvariants is referred to as their being immune-resistive. They can beat-back the varying degrees of immunity that we normally develop when vaccinated or after a COVID-19 infection. One might ask, therefore, why public health experts are still asking people to get vaccinated. Part of the answer lies in the fact that even though the protective factor of the vaccines may be diminished against these two subvariants, their protective factor is not zero. Nearly all of the prior COVID-19 versions are still around (Lamont, 7-14-22), and the vaccines can protect you against severe illness, hospitalization and death from those. People who are vaccinated are still more likely to get a milder version of the infection than those who are not vaccinated (Wendler, 2022). As with all versions of COVID-19, people who are at high risk due to age or debility, being overweight, having underlying health factors, as well as those with compromised immune systems, and those in higher-risk racial groups (Black, Hispanic, Indigenous people), should take every precaution to protect themselves as these infection numbers rise; and there is no indication that is going to change any time soon unless we make changes in what we are doing to protect ourselves. Both of these subvariants can and do infect people of any age, and now children as young as 6-months can be protected through vaccination.

Today the medical and healthcare communities are much better situated to effectively treat the many COVID variants and Omicron subvariants. We now have safe vaccines, effective antiviral medications, monoclonal antibody infusions, and improved care routines. We can get tested in a variety of places including right at home. If you test positive in a non-home testing location, your results will go to the Connecticut Department of Health.

People who test positive at home are not reflected in our already high positivity rates (10.5% on 7/15/22); the actual figure is much higher due to home-testing. This number should be below 5%). Connecticut DPH will forward your result to your local Department of Health. Here in Greenwich, a trained and compassionate case monitor/contact tracer from the Greenwich Department of Health will call you and guide you through the process of recovery, infection control, isolation/quarantine, and return to health.

Resources and References

CDC. (2022) COVID Data Tracker. Centers for Disease Control and Prevention; DHHS, Atlanta, GA. Retrieved from https://covid.cdc.gov/covid-data-tracker/#variant-proportions

Croft, J. (2022). Many People Becoming Reinfected as BA.5 Dominates New COVID-19 Cases. WebMD. Retrieved from https://www.medscape.com/viewarticle/977285

Katella, K. (2022). Omicron and BA.5: a guide to what we know. YaleMedicine. (Updated 6/6/22). Omicron and BA.5: A Guide to What We Know

Lamont, N. (2022) Governor Lamont Provides Update on Connecticut’s Coronavirus Response Efforts. Press Release. Retrieved from https://portal.ct.gov/Office-of-the-Governor/News/Press-Releases/2022/07-2022/Governor-Lamont-Coronavirus-Update-July-14

Matrajt, L., & Leung, T. (2020). Evaluating the Effectiveness of Social Distancing Interventions to Delay or Flatten the Epidemic Curve of Coronavirus Disease. Emerging Infectious Diseases, 26(8),

Sypsa, V. et al. (2021). Effects of Social Distancing Measures during the First Epidemic Wave of Severe Acute Respiratory Syndrome Infection, Greece. Emerging Infectious Diseases, 27(2). CDC. Retrieved from Effects of Social Distancing Measures during the First Epidemic Wave of Severe Acute Respiratory Syndrome Infection, Greece – Volume 27, Number 2—February 2021 – Emerging Infectious Diseases journal – CDC

Wendler, R. (2022) COVID-19’s BA.4 and BA.5 Omicron Subvariants: 12 questions answered. MD Anderson Cancer Center/MDAnderson.org. Retrieved from COVID-19’s BA.4 and BA.5 Omicron subvariants: 12 questions, answered

See also:

Long Covid Appears to Impact about 1 Out of 5 Covid-19 survivors