Brazzaville – Researchers in Botswana and South Africa have detected new sub-lineages of the Omicron variant of the SARS-CoV-2 and are carrying out further investigations to fully understand crucial traits such as infectivity and virulence.

The identified sub-lineages variant are BA.4 and BA.5. World Health Organization (WHO) experts are working with scientists and researchers in the two countries to deepen analysis of the sub-lineages which have so far been identified in four people in Botswana and 23 in South Africa. Outside Africa, the BA.4 and the BA.5 have been confirmed in Belgium, Denmark, Germany and the United Kingdom.

Currently there is no significant epidemiological difference observed between the new sub-lineages and known sub-lineages of the Omicron variant, which include BA.1, BA.2 and BA.3 sub-lineages.

“There is no cause for alarm with the emergence of the new sub-variants. We are not yet observing a major spike in cases, hospitalizations or deaths,” said Dr Matshidiso Moeti, WHO Regional Director for Africa.

“We are working with scientists in Botswana and South Africa to gain complete behavioural knowledge of these sub-lineages and supporting African countries enhance genomic surveillance to detect potentially dangerous variants and stay ahead of the virus,” Dr Moeti said.

WHO calls on countries to enhance genomic surveillance to better understand circulating SARS-CoV-2 variants, submit complete genome sequences and associated metadata to a publicly available database and report initial cases or clusters of cases linked with a variant of concern to infection to WHO.

Additionally, countries should undertake field investigations and laboratory assessments to improve understanding of the potential impacts of variants of concern on COVID-19 epidemiology such as severity, effectiveness of public health and social measures, diagnostic methods, immune responses, antibody neutralization or other relevant characteristics.

The Organization also recommends that countries sequence at least 5% of all positive samples. With support from WHO and other partners, Africa has made strides in ramping up sequencing capacity, having sequenced six times as many samples in the first quarter of 2022 compared with the same period in 2021.