China’s Sinovac announced that its COVID-19 vaccine candidate appears safe in the elderly, although it was slightly less effective in this population compared to younger adults.
The preliminary results come from an early to mid-stage trial of Sinovac’s vaccine candidate CoronaVac, in which the shot appeared to produce promising immune responses in three groups of participants.
Individuals in the three groups were given two shots of low-, medium- and high-dose CoronaVac, respectively. For 90% of study participants, a significant increase in antibody levels was observed.
Among older subjects, the levels of immune response were slightly lower than their younger counterparts – the detailed results have yet to be released by Sinovac, so it is unclear by exactly how much they differ.
Sinovac’s media representative Liu Peicheng told Reuters that the vaccine did not cause any severe side effects in the combined phase 1 and phase 2 studies involving 421 individuals aged at least 60 years old.
The Beijing-based biotech launched a large-scale phase 3 study of CoronaVac in early August and is set to be tested in both Indonesia and Brazil.
The Brazilian study will recruit nearly 9,000 healthcare professionals working in COVID-19 specialised facilities in 12 clinical sites located in several states across the country.
The company is also testing its vaccine candidate in Indonesia as the rate of new coronavirus infection cases is too low in China, making it difficult to recruit for a large-scale study.
Earlier this week, Sinovac’s chief executive Yin Weidong said that around 90% of the company’s employees, as well as their families, have been given the experimental vaccine under China’s emergency use programme.
Sinovac offered CoronaVac to around 2,000-3,000 employees and their families on a voluntary basis, said Weidong.
The data collected from this programme will help researchers to better understand the vaccine’s safety and tolerability, but will not be included in submissions to medical regulators as it is not part of registered clinical trial protocols.
He added that employees were informed of potential side effects before taking the vaccine, which potentially includes fatigue, fever and pain.