After a study showed that the AstraZeneca-Oxford vaccine was less effective in mild to moderate illnesses caused by the South African variant, the country changed the way the vaccine was distributed, as announced at the conference the World Organization for Health (WHO) announced this afternoon) Salim Abdool Karim, co-responsible for the Advisory Committee on Covid-19 in South Africa. Basically, the vaccine is given to approximately 100,000 people first and is only distributed after hospital admissions have been assessed. Tedros Adhanom Ghebreyesus, WHO Director-General, also said that the WHO Strategic Advisory Group on Immunization (SAGE) met this Monday to review this vaccine and that Tuesday they will be with the group responsible for discussing your recommendations will meet.
Tedros Ghebreyesus initially said that the AstraZeneca-Oxford vaccine was shown to be effective (generally) in serious illness or hospitalization, but the new variants brought unknown results. “The emergence of new variants raised questions about the impact on vaccines,” he said. Regarding this issue, South Africa temporarily suspended the distribution of this vaccine last weekend “after it was shown to be minimally effective in preventing the mild and moderate disease caused by the variant identified in South Africa,” said the director-general by whom. “This is worrying news.”
Salim Abdool Karim then explained the reasons for this postponement, first pointing out that different vaccines were monitored in different laboratory tests in South Africa. Five of the eight vaccines they monitor have already undergone these studies and have shown that “antibodies induced by the vaccine have greater difficulty neutralizing the South African variant.” While the Pfizer BioNTech vaccine had “minimal changes in neutralization activities”, at AstraZeneca-Oxford there was “a significant decrease in neutralization activity”. “We don’t quite understand what these lab results meant, and we need clinical results.”
Therefore, a study with a little more than 2000 young and healthy participants was carried out in which only mild to moderate illnesses were assessed in relation to the variant. The AstraZeneca-Oxford vaccine was only found to be 22% effective, which means that vaccinated participants were only 22% less likely to develop mild to moderate Covid-19 compared to subjects who received a placebo. “We are [também] unsure of the vaccine’s effectiveness in preventing serious diseases, ”he said. “We know it works against other variants, but we don’t have that confidence about the South African variant.”
So the country is considering changing the way the vaccine is distributed. The first step is now to consider giving the vaccine to 100,000 people and monitoring hospitalization rates. If they are below a set threshold, their effectiveness in preventing hospitalization can be demonstrated. This will restart your distribution. If this threshold is exceeded, other alternatives must be sought. “We do not want a situation in which we vaccinate a million people with a vaccine that does not effectively prevent hospitalization and serious illnesses,” said Salim Abdool Karim. “To do this more prudently, we need to do an assessment first and then do the distribution.”
The South African government’s vaccination program should begin with a million vaccines from AstraZeneca-Oxford in the next few days. These were mainly aimed at health professionals. The country had also announced more than 500,000 cans for March.
Tedros Ghebreyesus also stressed the importance of increasing the spread of vaccines as soon as possible, preparing new studies for them and being aware of their effects on forms of serious diseases. For all of these reasons, SAGE met to review the AstraZeneca-Oxford vaccine and “discuss new developments”. On Tuesday, the WHO Director General will chair the group to discuss the recommendations.