A clinical trial in China has shown that an inhalable COVID-19 booster vaccine is safe and effective in adults. Scientists led by Chen Wei of the Chinese Academy of Military Medical Sciences have developed an aerosolized adenovirus type-5 vector-based Covid-19 vaccine (Ad5-nCoV) administered by oral inhalation.
Chen’s group and researchers from the Jiangsu Province Center for Disease Control and Prevention conducted a randomized, open-label, controlled trial to evaluate the safety and immunity of the vaccine as a booster vaccine in 420 Chinese adults who had previously received two doses of inactivated vaccine. According to research published recently in the journal Lancet Respiratory Medicine, between September 14 and 16 last year, some randomly selected participants were given the low-dose or high-dose inhalable vaccine, while others received the same intramuscular vaccine as the previous two injections as a control group. .
The results showed that serum neutralizing antibody concentration of 744.4 in the low dose group and 714.1 in the high dose group was formed 14 days after the booster vaccine was given, which was significantly higher than the 78.5 concentration in the control group. Vaccine-derived neutralizing antibodies can bind to the coronavirus and prevent it from infecting cells. Also, only 26 participants in the low-dose group and only 33 participants in the high-dose group reported adverse reactions within 14 days of booster vaccination, according to the study. This figure is also significantly less than the 54 reported in the control group.
The researchers concluded that immunizing a heterologous booster with an aerosolized Ad5-nCoV is safe and highly immunogenic in previously vaccinated adults. Researchers are now planning a multicenter, randomized, double-blind, parallel controlled efficacy trial of an inhalable vaccine as a booster dose in Mexico following a series of primary immunizations with Ad5-nCoV.