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Omicron BA.4 / BA.5 Dominate RI, Spread Like Measles

[CREDIT: CDC] An image of the novel coronavirus that causes COVID-19. Relatively few children or young people are vaccinated against the disease. Kent County COVID risk is medium, and an Omicron vaccine is on the way.

[CREDIT: CDC] An image of the novel coronavirus that causes COVID-19. Relatively few children or young people are vaccinated against the disease. Kent County COVID risk is medium, and an Omicron vaccine is on the way.
[CREDIT: CDC] An image of the novel coronavirus that causes COVID-19. Few children are vaccinated. Kent County COVID risk is medium, and an Omicron vaccine is on the way. Omicron BA.4 / BA.5 is dominant in RI, and spreads like measles.
PROVIDENCE, RI — The Omicron sub-variants BA.4 / BA.5 now dominate RI COVID-19 infections, are as contagious as  measles, and elude immunity from vaccines and past infections.

How contagious is Omicron BA.5 / BA.4? Is it common?

“Measles is so contagious that if one person has it, up to 90% of the people close to that person who are not immune will also become infected,” according to the CDC.

Together BA.4 and BA.5 are now the dominant strains in the U.S., accounting for about 80% of COVID-19 infections, according to the Biden Administration. They’re also dominant in Rhode Island, where they make up a combined  76.5% of COVID-19 infections.

On June 11, the Centers for Disease Control and Prevention (CDC) reported the new, extra-catchy versions of the Omicron COVID-19 variant, BA.4 and BA.5 made up 2.85% and 4.27% of cases in Rhode Island. As of July 9, BA.4 and BA.5 in Region 1 New England states, including Connecticut, Maine, Massachusetts, New Hampshire, and Rhode Island, now make up 16.8% and 59.7% of cases, respectively.

The BA.4/BA.5 subvariant made up about 35 percent of cases nation-wide by June 22, according to Dr. Katelyn Jetelina, epidemiologist and biostatistician and author of the Your Local Epidemiologist blog.

BA.4/BA.5 is fast outcompeting BA.2 12.1, which made up 64.89% of COVID cases in Rhode Island on June 11. Now, BA.2 12.1 makes up 17.3% of cases, according to the CDC.

“BA.5 has arrived. An estimated 10-15% of Americans will be infected. Unfortunately, hospitalizations and death will follow, albeit at lower rates than we’ve seen before,” Jetelina wrote Wednesday about the rapidly-dominating variant.

BA.4 / BA.5 evades immunity

A recent study in the New England Journal of Medicine shows that neutralizing antibodies developed from a past BA.1 or BA.2 Omicron infection are up to 18 times less effective at  BA.4/BA.5 variants, according to a letter from researchers at Beth Israel Deaconess Medical Center, Boston, MA, published in the New England Journal of Medicine July 7.

However, reduced immunity still appears to protect from severe disease and death.

“On a population level, we expect our complex history of infection- and vaccination-induced immunity to continue to protect against severe disease,” Jetelina said.

How severe is BA.4 / BA.5?  Why avoid it?

“Early reports from South Africa indicated that most cases were mild—and that symptoms for this variant seemed to be different. “The reports show that patients in South Africa—many of whom were young—have had severe fatigue, but no loss of taste or smell,” says Lauren Ferrante, MD, a Yale Medicine pulmonologist,” according to

“There are many reasons to avoid an infection (can’t miss work; don’t want to feel crappy for a week or two; risks of long COVID; high risk for severe disease; live with vulnerable people),” says Jetelina.

COVID-19 BA.4 / BA.5: What should I do?

Jetelina noted the following precautions to avoid spreading the new variants and endangering friends and family:

  • Get vaccinated, or get your booster shots BA.4 and BA.5 may not be more deadly, but vulnerable people around you are still at some risk of serious illness and death if they become infected with the subvariants. In Rhode Island, most counties are at low risk of infection, but also low rates of vaccination among young people.
  • Over 50? Get your booster “If you don’t have your first booster, it’s beyond time. If you don’t have your second booster, get one now. Seriously. Schedule your appointment here. Do not delay. You will be able to get an Omicron booster this fall even if you get boosted now. Another booster now will not only prevent infection but will prevent severe disease. In the U.S., adults aged 50 and older with two booster doses had 4 times lower risk of dying from COVID-19, compared to people who received one booster dose,” Jetelina wrote.
  • High risk and COVID-19 positive? Get Paxlovid The oral anti-viral is safe and effective against severe disease. “You need to start the course within 5 days of symptoms or it won’t work well. You can get a prescription from your clinician. The FDA also recently authorized getting a prescription directly from a pharmacist. Here are some test to treat location options,” according to Jetelina.
  • Don’t use the CDC Community Levels map to decide when to use a mask  “This does not tell us when to wear a mask for individual protection. The old CDC transmission map is painted red (which doesn’t even take into account under-reporting) and shows 98% of Americans should wear a mask in crowded, indoor spaces if they don’t want to get sick. Transmission is high across the states and will get higher,” according to Jetelina.
  • Wear a mask, get fresh air “Ventilation and filtration really matter and are powerful tools. This is especially important in the middle of a heat wave while people head indoors. The short video below gives a very clear depiction of how COVID19 spreads through the air. Think of SARS-CoV-2 as being like smoke. It can spread even if you’re just whispering and can linger for hours, even once someone has left the room. Get that air moving. You can use a CO2 monitor to know your ventilation, if that’s helpful,” Jetelina wrote.


Use antigen tests to avoid exposing others to the virus “If you use antigen tests before seeing someone vulnerable,keep the following in mind:

  • If you have the virus and are asymptomatic, you can expect the average antigen test to catch 44% to 70% of cases. This is good but not perfect.
  • Be sure to conduct cadence testing: test 48 hours before the event and again the morning of. If they are both negative, I would feel comfortable proceeding.” Jetelina said.


Rob Borkowski
Author: Rob Borkowski

Rob has worked as reporter and editor for several publications, including The Kent County Daily Times and Coventry Courier, before working for Gatehouse in MA then moving home with Patch Media. Now he's publisher and editor of Contact him at [email protected] with tips, press releases, advertising inquiries, and concerns.

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