Research in high-impact factor journals:

Emergence of SARS-CoV-2

Omicron lineages BA.4 and BA.5 in South Africa

Nature Medicine (IF - 87.244)

National survey in South Africa reveals high tuberculosis prevalence among previously treated people

Lancet Infectious Diseases (IF - 71.421)

Wits researcher involved: Cathrine Scheepers (NICD), Kathleen Subramoney, Zinhle Makatini, Lesley Scott, Wendy Stevens, Nicole Wolter (NICD), Florette K Treurnicht, Jinal N Bhiman (VIDA), Anne von Gottberg (NICD)

Three lineages (BA.1, BA.2 and BA.3) of the severe acute respiratory syndrome coronavirus 2 (SARSCoV-2) Omicron variant of concern predominantly drove South Africa’s fourth Coronavirus Disease 2019 (COVID-19) wave.

The spike proteins of BA 4 and BA 5 are identical and are similar to BA 2 except for the addition of 69–70 deletion (present in the Alpha variant and the BA 1 lineage), L452R ss(present in the Delta variant), F486V and the wild-type amino acid at Q493. The two lineages differ only outside of the spike region

The study actively investigating the potential of a yet unidentified animal reservoir in the region To date, the only reverse zoonoses cases reported from the African region were in African lions and a puma in a private zoo in Johannesburg, South Africa

The study identified two new Omicron lineages (BA 4 and BA.5), which are associated with a resurgence in infections in South Africa approximately 4months on from the start of the Omicron wave This highlights the importance of continued global genomic surveillance and variant analysis to act as an early warning system, giving countries time to prepare and mitigate the public health effect of emerging variants

Wits researcher involved: Neil Martinson

People who reported a history of previous tuberculosis treatment contributed disproportionately to prevalent tuberculosis Of the 35 191 individuals participating in the survey, 2964 (8·4%) reported previous tuberculosis treatment. However, of 234 participants with bacteriologically confirmed pulmonary tuberculosis, 62 (26 5%) reported previous treatment, all of whom were culture-positive for Mycobacterium tuberculosis complex as per the study's case definition.

The crude prevalence of bacteriologically confirmed pulmonary tuberculosis was thus 3 2-times higher in participants who had previously had treatment compared with those who had not. High rates of prevalent tuberculosis among people who were previously treated have repeatedly been documented at the sub-country level in South Africa

It is worth emphasis that previously treated people are a key high-risk group for tuberculosis in South Africa, representing less than 10% of the adult population but contributing more than a quarter (26 5%) of undetected tuberculosis, and they should therefore be considered for targeted interventions.

Mathematical modelling showed that post-treatment follow-up with secondary preventive therapy among people who had previously completed tuberculosis treatment could reduce transmission, tuberculosis incidence, and mortality in high-incidence settings, and potentially save costs

*Read full study