The Department of Health says it has secured enough JnJ boosters for the estimated 480 000 healthcare workers who were vaccinated against Covid-19 from February to May this year under the Sisonke Trial for a phase 2 trial in collaboration with the SAMRC.  Acting Director-General of Health, Dr Nicholas Crisp told MedBrief Africa that the rollout will start as soon as the protocol for the trial is approved by SAHPRA. Dr Crisp says the department is also looking at evidence regarding the appropriateness of a Pfizer heterologous booster and how both the vaccines may be used, and the results compared.

He was reacting to a call by SAMA to make booster shots immediately available in the wake of evidence of waning efficacy of the JnJ jab after eight months and warnings of an impending 4th wave of the pandemic. Last week, an FDA panel consisting of outside experts voted to support Johnson & Johnson’s application to offer a booster shot of its vaccine, recommending that all individuals who were vaccinated with the single-shot J&J vaccine get a second dose, regardless of their age or any underlying conditions.

SAMRC President Prof Glenda Gray reiterated that while planning for the booster shots started In September, the researchers had to wait for the data on the effectiveness of the second jab.

“Policy needs evidence. You cannot make policy decisions based on media reports. We needed to see the data and the data on efficacy were presented to the Department, the moment we had it. By the time the FDA made the ruling, we had already put plans in place to provide boosters to healthcare workers. The Sisonke Boost study has been under discussion with the regulators for weeks, and we expect approvals shortly. The Ethics Committees also have to approve the study, which we expect to happen this week,” Prof Gray explained.

Prof Gray says although the immunogenicity of heterologous prime boosts using JnJ and Pfizer looked great in a small American study, the only data on durability currently available is that from US researcher and virologist, Prof Dan Barouch that showed differential decay in kinetics over time for the Pfizer arm, and greater stability for the JnJ shot and booster.

Prof Gray stressed that JnJ continued to show effectiveness against the Delta variant but that they will be evaluating its effectiveness again before the rollout of the boosters to HCWs.

“Based on data coming through on breakthrough infections, hospitalisation and deaths following vaccination with JnJ, we believe that there is still effectiveness. However, a formal analysis is underway,” Prof Gray said.