[imagesource: Reuters / Dado Ruvic / Illustration]

Unless you’re a healthcare worker in South Africa, chances are you have received the Pfizer-BioNTech COVID-19 jab, since dubbed Comirnaty.

According to Our World In Data, just north of 7,6 million South Africans are fully vaccinated, and more than 11 million have received at least one jab.

Talk around booster shots has heated up, with America’s Food and Drug Administration vaccines advisory committee meeting later this week to discuss Pfizer’s booster programme proposal.

Ahead of that meeting, Pfizer submitted a study by Kaiser Permanente Southern California, which found that “vaccine efficacy wanes over time naturally, “irrespective of variant”, rather than as a consequence of the Delta strain evading its jab”.

More from FT:

Pfizer presented data showing how the vaccine’s protection declined six to eight months after the second dose, becoming gradually less effective in two-month intervals. Vaccine efficacy fell about 6 per cent every two months after the second dose, down from 96.2 per cent a week after full vaccination to 83.7 per cent more than four months later.

The company also cited Israeli data showing that a third booster shot restored protection up to 95 per cent against Covid-19, documents filed to the FDA show.

Moderna, the company behind another vaccine used widely across the globe, also shared data showing that the protection afforded by its vaccine wanes over time.

Booster doses of vaccines made by Pfizer and Moderna for people with weak immune systems have already been signed off on.

Those questioning the efficacy of vaccines often point to Israel as an example, with data coming out of the country between December 2020 and July of this year showing an increase in the numbers of vaccinated people who caught the virus that causes COVID-19.

These are known as “breakthrough infections” and were most frequent in people who had been vaccinated early on in the country’s vaccination drive.

However, all data comes with caveats, as News24 explains in this excellent look at waning immunity and booster shots:

Despite the surge in cases, data from Israel suggests that the vaccines are still effective at keeping people out of hospital, even with infections caused by the highly transmissible Delta variant.

According to the report, the rate of hospitalisation in Israel was double for unvaccinated people under 60, and nine times higher for unvaccinated over-60s, proving, yet again, that the vaccines are holding up for severe outcomes, including death.

This has led some experts to argue that there isn’t a strong case for booster shots just yet, as vaccines remain effective at preventing severe disease, hospitalisation, and death.

Speaking last month, Shabir Madhi, professor of vaccinology at the University of the Witwatersrand (Wits), stressed exactly this:

“The evidence is clear – that waning of protection is against mild disease, not severe disease. The effectiveness against severe disease, for all of the vaccines, is sustained beyond eight and nine months, and remains above 90% for Pfizer, as an example – even with the Delta variant,” he said.

According to Professor Thomas Scriba, deputy director of immunology and laboratory at the South African Tuberculosis Vaccine Initiative, the waning of vaccine efficacy will differ from person to person:

He also touched on booster shots:

Vaccines boosters are nothing new. There is a requirement for occasional vaccine boosters, about once every decade, for diseases such as tetanus and yellow fever, said Scriba. Boosters are also required for the influenza virus every year. But there are interesting exceptions to this.

“For example, immune memory to the measles vaccination is remarkably long-lasting and booster vaccines are typically not necessary. But given the types of vaccines being used for Covid, and evidence from up to about one-year follow-up for Covid vaccinations, it is likely that the antibody and T cell responses will be more like those to yellow fever vaccination,” he explained.

Scriba believes South Africa should focus first on ensuring more people are vaccinated before considering rolling out booster shots, although those may be needed further down the line.

The UK has already announced a booster shot plan for older, vulnerable groups.

[sources:ft&news24]