There is no credible evidence that the current doses of vaccines have a lower protection against severe disease in relation to Covid-19.
A study in The Lancet medical journal has made this finding amid calls from some countries for vaccine booster shots against Covid-19. In its research, the paper said the current evidence did not appear to show a need for extra doses for the general population, because the efficacy of the vaccines remains high.
The Delta variant of Covid-19 has been found to be highly transmissible and was responsible for a sharp spike in the number of cases globally, pushing some countries to consider boosters. However, this decision should be evidence-based, and consider the benefits and risks for individuals and society, the peer-reviewed journal said.
For South Africa, officials say the question of booster shots is not a priority but should the need arise, there are enough vaccines available.
Given that some countries are struggling to vaccinate everyone, the Lancet report suggested that any gain made from boosters could not outweigh the benefits of providing protection to the unvaccinated. It further highlighted that the current variants of the virus had not yet evolved to a point where they could escape the memory immune responses induced by those vaccines.
Variant-based booster studies should be conducted before there is a need for them, The Lancet report said, and then adopt a similar strategy used with annual influenza vaccines, which are targeted at the circulating variant at the time.
Dr Sanet Aspinall, virologist for the Numolux Group that distributes the Sinovac vaccine, agreed: “There is probably a lot of truth [in the findings made by the researchers of the study on the considerations for boosters] because countries need to start vaccinating people instead of providing boosters to people who have already been vaccinated.
“If people have been vaccinated there’s some antibody level that will protect them if they come into contact with the virus. Whereas the unvaccinated population do not have any protection, so it makes more sense to protect the people that have not been vaccinated rather than spend the funds on booster shots. The boosters will come later.”
Professor Francois Venter, of the University of the Witwatersrand and the divisional head of Ezintsha, a group of South African academics and health professionals working with partners around the world, agreed that it was too soon for countries to start administering booster shots “especially when our current vaccines are working so well, and while only 18% of the population is vaccinated”.
“Rather focus on getting the over-60s vaccinated, and wait for data,” Venter said.
The Lancet study comes against the backdrop of countries such as Israel administering booster shots of the two-dose Pfizer vaccine to people aged 50 plus who were vaccinated in January. More than 2.8-million people in Israel have received the third dose since the beginning of August.
At the time the decision to administer a third dose was taken, Israel had reported that 50% of fully vaccinated individuals were among those who were infected with Covid-19, saying the vaccine effectiveness was at 40%.
“Previously we thought that fully vaccinated individuals are protected, but we now see that vaccine effectiveness is roughly 40%,” said Dr Sharon Alroy-Preis, the country’s director of public health services, in an interview with the American television and radio network CBS.
The director general of the Israeli health ministry, Nachman Ash, told Radio 103FM that preparations were underway to secure more vaccines in case there was a need to administer a fourth dose.
“We don’t know when it will happen; I hope very much that it won’t be within six months, like this time, and that the third dose will last for longer,” he said.
Both the UK and the US were planning to administer booster shots later in the month.
The report from The Lancet said randomised trials reliably showed the high initial efficacy of several vaccines, and were relatively easy to interpret. It said observational studies had proved to be less reliable in attempts to assess the effects on particular variants or the durability of vaccine efficacy, or both, and had substantial difficulties in estimating vaccine efficacy undertaken in the context of rapid vaccine roll-out.
The World Health Organisation has also called for a moratorium on Covid-19 booster shots. The fact that there was no equity in access to and distribution of vaccines remains a concern for the United Nations agency’s chief, Tedros Adhanom Gebreyesus.
More than 80% of the vaccine doses administered are in high and middle-income countries, with high-income countries administering about 50 doses per 100 people while low-income countries have only administered 1.5 doses per 100 people.
“I understand the concern of all governments to protect their people from the Delta variant, but we cannot accept countries that have already used most of the global supply of vaccines using even more of it, while the world’s most vulnerable people remain unprotected,” Ghebreyesus said in August.
In South Africa, the deputy director general in the department of health, Dr Nicholas Crisp, said during an interview on the Newzroom Afrika channel on Sunday that the government was considering booster shots for healthcare workers who were vaccinated in February.
The department’s spokesperson, Popo Maja, said “the issue of boosters is not a priority at the moment, but [the priority is] to reach as many people as possible before the next wave”.
“We do have sufficient vaccines for the general target population to receive at least one dose before we could consider booster jabs.”
Numolux Group virologist Aspinall said the Johnson & Johnson vaccine boosters should only be considered for health workers when there was data showing a diminished immune response from the drugs over time.
The South African Health Products Regulatory Authority (Sahpra) has responded to reports of deaths allegedly caused by vaccines.
Reports about the negative side effects of the vaccines prompted the regulator to investigate the deaths of 86 people said to have occurred after they were vaccinated between May and August.
Investigations and casualty assessments were done in 40 of these cases and 46 are still under investigation. Thirty-four of these cases were found to have been coincidental and had no relation to the vaccine, 13 were related to Covid-19 and one death resulted from a breakthrough infection.
There were six unclassified results because the information available was inadequate.
According to Sahpra, 2 770 reports of adverse events after immunisation were reported by patients through healthcare providers or its mobile app. More than 15.18-million vaccines had been administered by Tuesday and 11.03-million people had been vaccinated.
The University of the Witwatersrand’s Venter said the findings by Sahpra were not surprising in terms of the adverse events reported.
“It is not surprising that none of the deaths have been linked to the vaccine — serious events are exceedingly rare. Eventually one will, but the risk/benefit ratio is far in favour of the vaccine,” he said.
Some of the common side effects that were reported or are likely to be experienced include headaches, soreness around injection spot, fatigue, dizziness, pain, fever, nausea, laboured breathing, chest pain, chills and muscle aches.