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South Africa recently received 1 million doses of the COVID-19 AstraZeneca-Oxford vaccine and was poised to begin vaccinating healthcare workers, but yesterday, health officials announced a launch pause to investigate early findings that it offered little protection against mild to moderate. disease caused by the variant strain B1351 that is dominant in the country.
New questions arise about the vaccine as advisers to the World Health Organization (WHO) consider it this week for inclusion on the emergency use list, which if approved, would pave the way for low-income countries to receive your first doses through the COVAX program. The first shipments through COVAX depend on 350 million doses of the AstraZeneca-Oxford vaccine.
Incomplete table of serious impacts on results
The new findings, from a submitted preprint, come from researchers in South Africa and the UK. The study included 2,000 volunteers with an average age of 31 years. Along with minimal protection against mild to moderate disease, they also found that viral neutralization against the B1351 variant was substantially lower compared to the standard virus.
However, the team said they couldn’t assess protection against serious illness, hospitalization and death, because the study’s target population was younger and at low risk for those outcomes.
In a press release from the University of the Witwatersrand in Johannesburg, the team said that efforts are underway at Oxford to produce a second-generation version of the vaccine that targets variants similar to B1351.
Andrew Pollard, MBBS, PhD, lead investigator for the Oxford vaccine trial, said the study confirms that the virus will find ways to continue to spread in vaccinated populations, as expected, but with promising results from other vaccine trials in South Africa. They use a similar virus. The vector suggests that vaccines will continue to help ease the burden on health systems by preventing serious disease.
At a WHO briefing today, Salim Abdool Karim, MD, PhD, co-chair of South Africa’s COVID-19 advisory committee, said concerns about the efficacy of the B1351 variant vaccine deepened after Novavax reported a 89% efficacy in the UK, but only 49% in South Africa.
He said officials halted the launch of the AstraZeneca-Oxford vaccine to collect more clinical data to better understand the effect of the vaccine, especially given the uncertainty about the impact on severe disease.
He said there are several caveats about the new findings from the South African trial, including that the number of participants was small and the confidence intervals were wide, with an upper limit range of 60% approaching the study’s overall efficacy finding. phase 3 broader. He also said that the dosing interval in the study was short, compared to the new longer intervals proposed by AstraZeneca to improve the immune response.
One proposal South African officials are considering is a staggered rollout, which would involve vaccinating an initial 100,000 people to monitor the vaccine’s impact on severe disease, Abdool Karim said.
The B1351 variant was first found in South Africa, where it currently accounts for 80% to 90% of cases. Along with the P1 variant detected in Brazil, it contains the E484K mutation, which is believed to help SARS-CoV-2 evade immunity to vaccines and natural infection. Scientists in the UK recently reported that a small number of B117 variants have developed the E484K mutation, raising broader concerns that ongoing evolutionary changes may mitigate the impact of vaccination.
WHO advisers weigh emergency use
At today’s briefing, WHO Director-General Tedros Adhanom Ghebreyesus, PhD, said that the group’s Strategic Advisory Group of Experts on Immunization (SAGE) met today to review the AstraZeneca-Oxford vaccine, and that tomorrow it will be meet with the SAGE president to discuss their recommendations. .
In the coming days, the WHO hopes to make a decision on the list of emergency use of the AstraZeneca-Oxford vaccine, which would be the second, behind that of Pfizer-BioNTech. Emergency use would correspond to the AstraZeneca-Oxford vaccine manufactured at two sites, one at the Serum Institute in India and the other at SK Bioscience in South Korea.
Tedros said it is increasingly clear that manufacturers will have to adapt to the evolution of the virus, taking into account the latest variants for future vaccines, including booster shots, similar to the flu vaccine update process. He said it is vital that countries continue to report variants to WHO, which is expanding its mechanism to provide guidance to manufacturers and countries.
Seth Berkley, MD, CEO of Gavi, said that as the science evolves, health officials are learning more as they work with vaccines, noting that discussions like the one now taking place are expected about the AstraZeneca vaccine in South Africa. He said there may also be changes in the way vaccines are used and in the composition of vaccines.
He said that while officials await guidance from SAGE, it appears that the AstraZenca vaccine is effective and has been reviewed by several strict regulatory agencies, and officials hope to continue implementing the vaccine for COVAX while they monitor further studies.
Richard Hatchett, MD, executive director of the Coalition for Epidemic Preparedness (CEPI), said at today’s briefing that CEPI has announced more funding for studies to optimize and extend the use of existing vaccines, which could involve “mix and match” strategies. combine “enhance immune response.
Other world headlines
- France, among the countries that reported a recent spike in infections and stress on their healthcare system, now reports a promising decline in cases in the past 4 days, according to Reuters.
- China, for the first time in 2 months, reported no new local cases, according to the daily report of the National Health Commission. The country has been fighting groups and hot spots in the northeast part of the country.
- The WHO-led international joint team investigating the zoonotic origin of SARS-CoV-2 will hold a press conference tomorrow in Wuhan at 4 p.m. Wuhan time, the WHO said today in an email to reporters.
- The global COVID-19 total recently surpassed 106 million cases and stands at 106,395,021, with 2,322,611 deaths, according to the Johns Hopkins online panel.
