Since Omicron was first discovered in late 2021, it has stubbornly refused to go away. Highly contagious even compared to previous versions of COVID, it led to a record winter surge earlier this year – and is believed to have become even more contagious since then. The Omicron has mutated several times, first from BA.1 and BA.2 to BA.5, the version now spreading across the country along with the similar BA.4 subtype. Projections from the US Centers for Disease Control and Prevention (CDC) estimate that in the week ending July 9, BA.5 accounted for 65 percent of COVID infections based on samples collected, with BA.4 accounting for 16.3 percent. If accurate, that estimate would be up from 53.8 percent last week and 39 percent the week before. A file photo shows a COVID testing site and pedestrians wearing masks in New York on June 6, 2022. Some scientists believe the BA.5 subtype of COVID may be more contagious than previous types. John Smith/Getty/VIEWpress “The Omicron BA.5 subvariant is the worst version of the virus we’ve seen,” Eric Topol, founder of the Scripps Research Translational Institute and a professor of molecular medicine there, wrote in his blog in late June. “It takes immune evasion, already extensive, to the next level, and, as a function of that, enhanced transmissibility, well beyond Omicron (BA.1) and other variants of the Omicron family that we’ve seen.” According to Topol, the genetic sequence of BA.5 showed that it has mutated significantly from early versions of Omicron, making it harder for our bodies to recognize its spike protein and provide immunity. Topol is not the only one who has warned about BA.5. In a press briefing on July 12, CDC Director Rochelle Walensky said that “people with prior infection, even with BA.1 and BA.2, are still at risk for BA.4 or BA.5.” BA.5 is thought to take transmissibility and immune evasion to another level. Two key questions now are what this means for vaccines and whether BA.5 causes more severe disease in people who get it. In the most recent technical update on COVID variants published on 24 June, the UK Health Safety Agency (HSA) addressed the vaccine issue, noting that there was insufficient data at the time to know for sure how well the vaccines work. vaccines against BA.5. However, it said preliminary analyzes showed that “the protection afforded by the vaccines likely remains comparable to that observed previously.” Walensky reiterated the point at Tuesday’s press briefing, stating that while data on the effectiveness of the BA.4 and BA.5 vaccines were still being collected, “we know that vaccine effectiveness against severe disease and death remains high for other subclasses Omicron and possibly also for BA.4 and 5.” It is currently not known whether BA.5 causes more severe disease than other Omicron subtypes. In his blog, Topol noted that there was a study showing that BA.4 and BA.5 caused worse disease than BA.2 in hamsters, but animal studies are not necessarily accurate in predicting what will happen in humans . In its June 24 report, the UK HSA noted that the risk of hospitalization had been increasing since April this year, but said the effect was small and the reason behind it was unclear. Professor Francois Balloux, director of the University College London (UCL) Genetics Institute (UGI) in the UK, had a more robust view. On Wednesday, he tweeted: “We have massive data on BA.5 hospitalization/death rates, preprints with huge sample sizes coming out left, right and center, all showing no increase in virulence [severity] above BA.1/BA.2.” We have huge data on BA.5 hospitalization/death rates, preprints with huge sample sizes coming out left, right and center, all showing no increase in virulence over BA.1/BA.2. However, half the scientific community and most of the media were fixated on a few 🐹🐹🐹 who lost weight… — Prof. Francois Balloux (@BallouxFrancois) July 13, 2022 Balloux also said the CDC’s data on the BA.5 rate of U.S. cases “does not capture the complexity of the current situation.” Finally, there is case evidence. CDC data show that the seven-day moving average of new U.S. COVID cases has been around between 100,000 and 110,000 for a few weeks, though it jumped to 123,365 on July 12. Online statistics tool OurWorldInData, which uses Johns Hopkins University’s COVID data, shows that some countries, including France, Italy, Germany, Switzerland and the United Kingdom, have all seen recent spikes in daily positive cases per one million people—although the variation behind the assumptions was not specified. In a statement to the media on July 12, the White House said that BA.5 “has the potential to cause an increase in the number of infections in the coming weeks” and that “vaccines remain our most important tool” to protect people . The Biden administration also said it would continue to provide antiviral drugs like Paxlovid to health services.
