Pharmaceutical company Pfizer on Thursday announced that a trial for their Omicron-specific booster vaccine, aimed at fighting infections caused by the BA.4 and BA.5 subvariants, has shown great promise.

The trial was only for adults.

According to a statement by the company, serum collected from participants seven days after administration of the booster showed a substantial increase in the Omicron BA.4/BA.5 neutralising antibody response above pre-booster levels. The company added that the booster was well tolerated and had a safety profile similar to the original vaccine.

Pfizer said that additional data measuring responses after a month of having received the booster vaccine are expected soon. 

The statement added that the data suggests the booster will provide better protection against the BA.4 and BA.5 subvariants of the virus. 

“Since the earliest days of the pandemic, we have strived to transparently share data regarding our Covid-19 vaccines in the interest of public health,” Pfizer CEO Albert Bourla was quoted as saying. 

“While we expect more mature immune response data from the clinical trial of our Omicron BA.4/BA.5-adapted bivalent vaccine in the coming weeks, we are pleased to see encouraging responses just one week after vaccination in younger and older adults. 

“These early data suggest that our bivalent vaccine is anticipated to provide better protection against currently circulating variants than the original vaccine, and potentially help to curb future surges in cases this (northern hemisphere) winter.”

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The booster was designed after it became clear that the Omicron variant had the ability to get around vaccine-induced immunity and, as a result, people who previously had Covid were at greater risk of getting it again as long as BA.4 and BA.5 are the main viruses in circulation.

The spokesperson for the SA Health Products Regulatory Authority, Youven Gouden, said they were waiting for an answer from Pfizer before considering their application to register the booster locally.

According to the National Institute for Communicable Diseases (NICD), the estimated reproductive number for the virus is the number of people who will catch the virus from an infected person. If this number is one, the number of infections remain stable. If it is less than one, the number of cases decline, and if greater than one, it is an indication of an increase in cases.

The latest report, based on data up to 30 September, shows that this number is above one for Gauteng and the Western Cape. But the report adds that the number of Covid tests being done is at the lowest number it has been since the start of the pandemic, and that this might mean these numbers are an underestimate.

In the NICD’s weekly testing summary, analysts added that the positivity rate (the percentage of cases testing positive out of all tests done) had jumped to 7.3% from 6.6% the previous week. The highest positivity rate was found in Gauteng (around 10%), followed by the Western Cape (8%) and Limpopo and the Eastern Cape, each on 7%.

The latest available data from the the SA Medical Research Council (SAMRC)  showed a sharp increase of SARS-CoV-2 particles in wastewater in the Western Cape. 

In a statement, MRC president Prof Glenda Gray said there were sharp increases in the concentrations of SARS-CoV-2 RNA in several wastewater treatment plants in Cape Town, as well as in the Western Cape towns of De Doorns, Rawsonville and Worcester during the past week. The statement said these concentrations have not been seen for many months. 

“The increase in SARS-CoV-2 RNA concentrations in our wastewater programme coincides with an increase in the proportion of positive Covid-19 tests recently reported by the National Institute for Communicable Diseases,” Gray said.  

Prof Angela Mathee, a member of the SAMRC wastewater surveillance team, said that at this stage similar increases in SARS-CoV-2 RNA concentrations in wastewater have not been observed in the remaining five provinces (Gauteng, northern KZN, Limpopo, Eastern Cape, Free State) in the council’s programme. 

“We will be paying close attention to next week’s results to ascertain further changes, should they occur,” said Mathee. 

“Over the next few weeks, it may be prudent for those at risk to revert to basic protective measures such as avoiding, or wearing masks in, crowded indoor spaces or when caring for people who are ill, being fastidious about hand hygiene and keeping up to date with Covid vaccinations or booster shots,” she added. DM/MC