According to the Centers for Disease Control and Prevention, the coronavirus subvariants Omicron BA.4 and BA.5 now account for approximately 35 percent of cases in the United States. The subvariants are well on their way to achieving dominance at a faster clip than previous subvariants, including the current reigning subvariant, BA.2.12.1, which is now on the decline.
The pair, which share the same mutations in their SARS-CoV-2 spike proteins but have differences elsewhere in their genomes, are expected to achieve dominance “within weeks,” Dr. Shishi Luo tells Ars. Luo is the head of infectious diseases at Helix, a California-based population genomics and viral surveillance company that works with the CDC to help track emerging coronavirus variants nationwide.
It is not clear exactly what will happen in this last phase of the pandemic. What we know so far of the two subvariants is mixed.
Bad and good news
When BA.4 and BA.5 were first detected in South Africa in April, it quickly became clear that the two can evade immune responses from vaccination and past infections, even infections from previous omcron variants.
On Wednesday, the Boston researchers published data in the New England Journal of Medicine that reinforced these findings. The latest data found that people who had been vaccinated and boosted had 21 times lower neutralizing antibody titers against BA.4 and BA.5 than levels against the original version of SARS-CoV-2. And the neutralizing antibody levels were also 3.3 times lower than the levels against BA.1. Similarly, in people who had previously been infected with BA.1 or BA.2 (even most of whom had been vaccinated), the levels of neutralizing antibodies against BA.4 and BA.5 were still almost 3 times lower. compared to the levels against BA. .1.
Additionally, a recently published preliminary study found that BA.4 and BA.5 appeared to cause more severe disease in hamsters than BA.2 and BA.2.12.1.
But there is some good news so far: data on hospitalizations from other countries where BA.4 and BA.5 have already increased, including South Africa, suggests that the variants aren’t causing more serious illness and hospitalizations in humans.
So with the antivirals still effective and the vaccination still protecting against serious illness and death, Luo says it’s not the time to really worry. “I don’t think it’s necessary,” Luo said of the incoming wave.
But, as BA.4 and BA.5 move closer to dominance in the United States, making them the fourth and fifth omicron subvariant to dominate cases only this year after BA.1, BA.2 and BA.2.12.1, the question hangs: What’s next?
With BA.4 and BA.5 springing up in South Africa weeks ago, we have had the opportunity to see the next wave coming. But “right now there doesn’t seem to be any other variations on the rise,” Luo said. There are always a few virus samples here and there that don’t have an assigned lineage yet, which may be new variants, but none seem to speed up, infecting a growing number of people, he said. This means that BA.4 and BA.5 could enjoy a longer reign than their predecessors in the absence of emerging usurpers.
“But you know, that may change in the next few days,” Luo said. “I wouldn’t put it beyond this virus to mutate once again and let there be yet another wave.”
Federal regulators and vaccine manufacturers are preparing for omicron subvariants to be with us at least in the fall and winter. The Food and Drug Administration is preparing to authorize next-generation vaccines and boosters for the fall that could counter a seasonal surge. Expert advisors from the regulator will meet next week, June 28, to discuss the formulation of those next-generation vaccines. The best candidates are those who target omicron.
Short and long term plans
On Wednesday, Moderna released preliminary first-line data it will submit to the FDA, showing that its combination (bivalent) vaccine targeting both the original version of SARS-CoV-2 and the original omicron variant may increase protection against BA. 4 and BA.5. Moderna claims that the bivalent booster, dubbed mRNA-1273.214, can increase the levels of neutralizing antibodies against BA.4 and BA.5 up to 6 times.
“In the face of the continued evolution of SARS-CoV-2, we are very encouraged that mRNA-1273.214, our leading drop recall candidate, has shown high neutralizing titers against the BA.4 and BA.5 subvariants, which represent an emerging threat to global public health, “Moderna CEO Stéphane Bancel said in a statement. “We will be sending this data to regulators urgently and are preparing to deliver our next generation bivalent booster starting in August, in anticipation of a potential increase in SARS-CoV-2 infections due to omicron sub-variants at the start. autumn “.
While Moderna’s near-term outlook is upbeat, Luo is concerned about continued viral evolution and our diminishing potential to detect new variants. As people try to get through the acute phase of the pandemic, people send fewer samples for testing. “Looking ahead, we must understand, there will be [enough samples]? … If not, will there be enough people who will report to urgent care, health systems or hospitals, where there is an opportunity to take a sample and send it for sequencing? I think there is not yet a system that does this on a large scale, “Luo said.
Although Helix is looking for ways to set up such surveillance systems, Luo says a broader national strategy is needed to keep up with the variations. While we don’t think there is another variant on the horizon right now, it seems we need a plan on how, as a country, we will deal with the answer, “he said.” We can not keep hoping it will go. away on its own. “In a worst-case scenario that presents another variant that hinders treatments and vaccines,” we don’t want to go back to square one, right? We need a plan. “