AstraZeneca disclosed that its experimental COVID-19 vaccine AZD1222 triggered a robust immune response in elderly and older adults, similar to that previously seen in healthy study volunteers aged between 18 and 55. Adverse events associated with the vaccine, which is being co-developed with the University of Oxford, were also found to be lower in older adults.
The updated findings were based on an analysis of previously conducted interim safety and immune-response data carried out on a subset of older participants, and showed positive outcomes for adults over age 56, including the higher-risk group of those 70 and older, AstraZeneca and the University of Oxford said. In preliminary data from a phase 1/2 trial, published in The Lancet in July, AZD1222 was found to have induced both antibody and T-cell responses for at least 56 days in healthy volunteers aged between 18 and 55 years.
The new phase 2 data, which the University of Oxford said were discussed at a research conference, also point to a lower level of expected side effects from the vaccine among older people, such as potential fever, body aches and swelling at the injection site. The analysis showed that such reactions were lower in adults age 56 and older than in younger adults, with AstraZeneca noting that the reactions also lessened after the second dose of the vaccine.
“It is encouraging to see immunogenicity responses were similar between older and younger adults and that reactogenicity was lower in older adults, where the COVID-19 disease severity is higher,” an AstraZeneca spokesman said. Meanwhile, a representative from the University of Oxford stated that the findings mark a “key milestone” in the development of AZD1222, and “[reassure] us that the vaccine is safe for use, and induces strong immune responses in both parts of the immune system, in all adult groups.” The university added “these early results covering trial volunteers from the UK in the 56-69 and 70+ age groups have been submitted to a peer-review journal, and we hope to see their publication in the coming weeks.”
Moderna’s coronavirus vaccine candidate mRNA-1273 has also demonstrated the ability to elicit immune responses in both younger adults aged 18 to 55, as well as older populations.
Restart of US study
AZD1222 is currently undergoing evaluation in a Phase III study, the US arm of which was cleared to resume late last week. The study had been halted since September 6 after a participant developed neurological symptoms.
Meanwhile, a report Monday in the UK newspaper The Sun said staff at a major London hospital trust have been told to be ready to receive the first batches of AstraZeneca’s candidate vaccine on the week starting November 2. However, UK health secretary Matt Hancock indicated that while vaccine development was “progressing well,” he anticipates “the bulk of the roll out to be in the first half of next year,” although he did not rule out the possibility of some people receiving it this year. “We’re doing the preparatory work now for how that will be rolled out…and we’re doing the logistical work,” Hancock said, adding “preparing for a rollout and actually having the stuff to roll out are two different things.”