Current majority of US COVID-19 infections caused by BA.2 subvariant

As restrictions ease across the country, some experts warn that BA.2 could cause another surge of infections. Graphic by HARRY LADA, Art Director

The World Health Organization (WHO) announced March 22 that BA.2, a subvariant of the Omicron variant, has become the most dominant form of COVID-19 worldwide. 

BA.2 made up an estimated 86% of COVID-19 infections in the United States last week, according to the Centers for Disease Control and Prevention — which is equal to the percentage of BA.2 cases globally reported to WHO between Feb. 16 and March 17.

Andrew Noymer, a professor of population health and disease prevention at the University of California, Irvine (UCI), told The Panther that experts are still unsure whether BA.2 will wreak the same havoc on the United States as the original Omicron variant, known as BA.1, did earlier this year. 

“Based on what we saw with the original Omicron variant, BA.2 seems to be the perfect storm of being less deadly on the individual level but so highly transmissible,” Noymer said. “In parts of the U.S. like the Northeast, there are some signs of a wave forming.”

According to UCI Infectious Disease Science Initiative Director Sanghyuk Shin, BA.2 is at least 30% more transmissible than BA.1. Though the true extent of the subvariant’s transmissibility has yet to be determined.

“Because COVID-19 is an RNA virus, mutations occur as it replicates and spreads,” Shin said. “Even though both (BA.1 and BA.2) are in the same family, they have many genetic differences.”

BA.1 has about 60 mutations that are not found in the ancestral COVID-19 virus that first surfaced in Wuhan, China. BA.2 shares many of these mutations along with 28 other mutations unique to the subvariant.

Both variants were detected last November in South Africa. BA.1 quickly became the most dominant strain worldwide, while BA.2 lingered behind before eventually finding its way to larger communities. BA.2 has since exploded across parts of Africa, Asia and Europe. 

“When we see spikes and surges in other places across the globe, it is only a matter of time before it is going to hit the U.S.,” Shin said in an interview with The Panther. “(Between Feb. 27 and April 2), the BA.2 variant went from comprising 15% of cases in the U.S. to 72%.” 

So far, evidence shows that symptoms caused by BA.2 are not more severe than those from BA.1 for vaccinated people and those previously infected with COVID-19. However, with less than half of the United States population boosted with their vaccinations, some experts, including Shin, are concerned. 

“We know that when there is a huge wave, immunocompromised people ⁠— even if they are vaccinated ⁠— are at a higher risk for hospitalization and death,” Shin said. 

Shin hopes that the Omicron wave earlier this year will provide Americans sufficient protection against BA.2. In contrast, Noymer remains uncertain that immunity provided from the omicron wave will be enough to prevent another surge. 

“COVID-19 epidemiology is sometimes a bit mysterious,” Noymer said. “But we cannot assume that the population-level immunity on the heels of the original Omicron wave will protect us against a BA.2 wave.”

Chapman University lifted its indoor mask mandate March 3. Following the return to campus after the spring break, the university is also no longer requiring students to have their daily COVID-19 screenings checked and has dismissed compliance officers from their stations on campus.

Jerika Lam, a professor at the university’s School of Pharmacy and Chapman’s viral infection specialist, told The Panther the university community needs to realize that the pandemic is not yet over. 

Healthcare systems are still reeling from the surge in Omicron cases early this year. Although the United States Senate has closed on $10 billion of emergency funds for pandemic prevention efforts, that total is less than half of the $22.5 billion the Biden administration initially requested. 

“We’ve achieved so much in the past two years, and I do not want us to lose all of that progress,” Lam said. “I hope that we, as an intellectual community, can look back on our mistakes in 2020 and 2021 and take some preventative measures to make sure that we don’t fall backwards.”

Even as the United States nears 1 million deaths from COVID-19, Noymer notes that national concern about the pandemic has begun to deteriorate. Nationwide testing is on the decline despite the fact that testing data provides the basis of the Center for Disease Control and Prevention (CDC)’s new guidelines on when masking should be resumed. 

Without access to accurate testing, individuals, communities and experts may not be able to predict when and if a new surge of cases will hit. Epidemiologists are relying more and more on testing wastewater systems in order to detect important trends in COVID-19. 

“People in public health are kind of stuck between a rock and a hard place,” Noymer said. “People are getting fed up with restrictions. We know that COVID-19 fatigue is very real.”

According to Lam, much is still unknown about the long-term consequences of contracting COVID-19. Preliminary studies have indicated that even after symptoms fade, long-term organ and respiratory damage is possible. 

“Enjoy life, but please take precautions and be safe,” Lam said. “I don’t want us to be another number.”

Editor’s Note: Since the development of this story, several other COVID-19 subvariants of the original omicron (BA.1) strain and the BA.2 variant were discovered in the U.S.

A “handful of cases” of omicron XE were reported in the states as of April 15, according to the Washington Post. The XE subvariant was first detected in the United Kingdom and is a hybrid of both the BA.2 and BA.1 variants.

The New York State Department of Health also announced the emergence of subvariants BA.2.12 and BA.2.12.1 in an April 13 press release, which state officials affirmed to be highly contagious and responsible for 80.6% of COVID-19 infections in New York.

BA.2.12.1, which is thought to harbor a mutation that enables increased transmissibility, has been found in six other countries as of April 15. However, the U.S. still maintains the most cases of the subvariant globally — though the majority of these incidents have been localized to central New York.