SAO PAULO (Reuters) – A COVID-19 vaccine developed by China’s Sinovac Biotech is likely to be as effective for the elderly as it is for other adults, a senior official at the Brazilian biomedical institute conducting late-stage trials told Reuters on Tuesday.
Ricardo Palacios, medical director for clinical research at the Butantan Institute, said his expectations were based on a Phase 1 and 2 study of the vaccine, called CoronaVac, with older volunteers in China, which is pending publication.
He said results from that study will show immune responses were about as widespread among participants aged 60 years and older as they were in 18- to 59-year-olds — about 97% of whom showed antibody-related immune response.
“From that, we can infer that age is not such a relevant factor in the immunogenicity and it shouldn’t be for efficacy either. That’s what this fact seems to suggest,” Palacios said in a telephone interview.
He declined to comment on efficacy data from Brazil’s Phase 3 trial, which was expanded to some 13,000 volunteers in September, adding elderly participants.
Last week, Butantan delayed releasing the results of that trial for the third time, citing contractual obligations to Sinovac and adding to concerns about the transparency of the Chinese vaccine maker’s research.
Last week, Turkish researchers estimated that CoronaVac was 91.25% effective based on an interim analysis, but a Butantan official said its research showed efficacy between 50% and 90%.
Palacios said results from CoronaVac trials in Brazil and other countries could not be compared or consolidated because of differing selection criteria for participants.
Butantan will only use data from its trial in Brazil when seeking approval for the vaccine from Brazilian health regulator Anvisa, he said.
(Reporting by Eduardo Simoes; Editing by Brad Haynes and David Gregorio)