New data from scientists and vaccine makers Moderna and Pfizer/BioNTech suggests that a newer, highly mutated variant of the virus that causes Covid-19 is not as alarming as some experts had feared when it was first detected several weeks ago, Reuters reported the other day. Nicknamed “Pirola” on social media, the BA.2.86 Omicron subvariant is being tracked by both the World Health Organisation (WHO) and the US Centers for Disease Control and Prevention (CDC).
Covid infections and hospitalisations have been rising in the US, Europe and Asia, but are well below previous peaks. The weekly US hospitalisation growth rate slowed for three consecutive weeks in August, according to CDC data for the week ended August 26. The WHO has reported finding BA.2.86 in at least six countries. According to CDC data, the EG.5 subvariant, a descendant of the Omicron lineage nicknamed “Eris” on social media that originally emerged in November 2021, accounts for about a fifth of current US Covid cases. A variant nicknamed “Fornax,” officially FL.1.5.1, is the next largest at 14.5% of US infections, and represents a growing share of East Coast Covid cases. A wide range of other variants account for smaller shares of the total, with BA.2.86 currently representing less than 1%.
It was on August 31 that Qatar’s Ministry of Public Health (MoPH) announced detecting new cases of EG.5, clarifying that the recorded cases were minor and did not lead to hospitalisation then. An MoPH statement explained it was closely monitoring the epidemiological situation in relation to the new Covid-19 sub-variants. Earlier in August, the WHO declared the EG.5 a variant of interest. EG.5 is an off shoot of the highly contagious Omicron variant and has to date been reported in more than 50 countries.
Dr David Dowdy, an infectious disease epidemiologist at Johns Hopkins Bloomberg School of Public Health, US, believes FL.1.5.1 will become the predominant Covid variant in the coming months, but he does not expect an infection wave like the one driven by Omicron last winter.
Dr Dowdy suggested that the current surge in cases may be due to immunity from vaccination and infection wearing off some since the last surge. Scientists have been keeping an eye on BA.2.86 because it carries more than 35 mutations in key portions of the virus compared to XBB.1.5, the dominant variant through most of 2023.
The dramatic changes - on par with the genetic shift seen in the Omicron variant compared with its Delta predecessor - raised concerns that the new variant could cause a major surge. Experiments testing versions of the virus in two US independent laboratories suggest that is unlikely, said Dr Dan Barouch, director of the Center for Virology and Vaccine Research at Beth Israel Deaconess Medical Center in Boston, whose lab led one of the studies. His team tested lab-made versions of the virus in people who were vaccinated or previously infected and found that antibodies against the variant were comparable or slightly higher than those against current circulating variants.
Experiments done in the lab of Dr David Ho at Columbia University, as well as by teams in Sweden and China, had similar findings. Dr Barouch’s studies also suggested that newly updated vaccines will raise antibody responses “to some extent” against all of the currently circulating variants, including BA.2.86. Moderna last Wednesday said clinical data showed that its retooled Covid vaccine generated a nearly 9-fold increase in human antibodies that can neutralise BA.2.86.
Pfizer said on Wednesday that its updated Covid shot showed neutralising activity against BA.2.86 and EG.5 in studies conducted on mice. The updated shots are being reviewed by the US Food and Drug Administration and are expected to be available this month.