Despite concerns over the highly transmissible Delta variant of Covid-19, which has spread to 85 countries and has become the dominant strain in Gauteng province, the Johnson & Johnson and Pfizer vaccines remain effective, according to the limited data available.
The significant increase in Covid-19 infections in Gauteng has been largely driven by the Delta variant, the National Institute for Communicable Diseases (NICD) confirmed this week.
Accounting for 53% of infections in the province, the variant is 97% more transmissible than the original lineage of the SARS-CoV-2. On Wednesday, the department of health’s daily Covid-19 report showed that Gauteng had more than 85 000 active Covid-19 cases.
People who were previously infected with the formerly dominant Beta variant ― first detected in South Africa ― might be reinfected with the Delta variant.
“From the small dataset that we have seen reported nationally, it appears that there is a risk of reinfection with the Delta variant,” says Alan Christoffels, the director of the South African National Bioinformatics Institute, reiterating that “this is an active area of enquiry [and] research so we can only respond to the data at hand”.
Also drawing his response from limited available data, Wolfgang Preiser, the head of medical virology at Stellenbosch University, says being infected with the Beta variant during South Africa’s second wave of the pandemic “will not provide very good immunity against the Delta variant”.
Whether this lack of immunity will change the expectation of how the third wave progresses remains uncertain, says Preiser, but “it might contribute to what we are seeing in Gauteng”.
In the UK, the Delta variant continues to drive a sharp increase in Covid-19 cases consistent with previous pandemic waves during 2020-21, The Lancet journal reported on 28 June.
The UK recorded 26 068 new infections on Wednesday, its biggest daily increase since January.
According to the journal, daily hospital admissions and the number of patients requiring mechanical ventilation are increasing in both England and Scotland “despite the ongoing roll-out of widespread vaccination in the UK”.
The Oxford AstraZeneca vaccine — which is no longer approved by the South African Health Products Regulatory Authority — forms the basis of the UK’s vaccination programme. It also forms the core of the global Covax programme, which aims to ensure equitable vaccine access across the world.
South Africa’s vaccination programme currently includes two vaccines — the single-shot Johnson & Johnson and the double-shot Pfizer vaccine.
Pfizer offers 80% protection against the Delta variant after two doses, but there is no data yet to indicate the effectiveness of the J&J vaccine, according to Marvin Hsiao, a virologist at the University of Cape Town(UCT)/Groote Schuur Complex of the National Health Laboratory Service.
Emeritus professor in public health medicine at the UCT Jonny Myers says because the AstraZeneca vaccine is a similar type to the J&J vaccine “it is very likely that [the] J&J will be equally protective against severe Covid, hospitalisation and death”.
“The UK’s experience shows that Pfizer is [also] very effective against the Delta variant,” adds Myers. “Double vaccinated people will not get severely ill and will not die.”