MODERNA and Pfizer announced yesterday that their modified Covid-19 vaccines have demonstrated robust effectiveness in tests against the highly mutated BA.2.86 sub-variant of the coronavirus, Reuters reported.

Moderna said its vaccine resulted in an 8.7-fold increase in neutralising antibodies against BA.2.86, nicknamed “Pirola”, compared to the natural antibody response in untreated people, in clinical trials. The World Health Organization (WHO) and the US Centers for Disease Control and Prevention (CDC) are monitoring this variant closely.

Moderna infectious diseases head Jacqueline Miller said this was “positive news for individuals preparing to receive their autumn booster shots”.

She said the data should “reassure” regulators.

Pfizer reported that its updated vaccine, developed in collaboration with BioNTech, produced a strong antibody response against BA.2.86 in preclinical studies conducted on mice.

Moderna, Pfizer/BioNTech, and the newcomer Novavax have all developed versions of their vaccines targeting the XBB.1.5 sub-variant, which has dominated most of 2023. 

These vaccines are expected to be rolled out in autumn.

The CDC has previously indicated that BA.2.86 may have a greater ability to cause infections in people who have previously had Covid or received vaccine shots. The Omicron offshoot carries more than 35 mutations in key parts of the virus, unlike XBB.1.5, the target of the updated vaccines.

Experts believe that although it is essential to monitor the variant, it is unlikely to trigger a wave of severe disease and fatalities due to the widespread immunity established through mass vaccination and prior infections.

Moderna has shared its new findings with regulatory authorities and submitted them for peer review publication. 

While the revised vaccine has not yet received approval from the US Food and Drug Administration, it is expected to become available later this month or in early October.

BA.2.86 has been detected in several countries, including Switzerland, South Africa, Israel, Denmark, the US, and the UK, according to a WHO official. – September 7, 2023.