Inhalable vector-based COVID-19 vaccine increases antibodies 300-fold, better than mRNA & inactivated type as booster
Published: Oct 17, 2021 07:09 PM
CanSinoBIO's vaccine Photo: VCG

CanSinoBIO's vaccine Photo: VCG

According to latest lab studies, China’s first aerosolized COVID-19 vaccine has showed an increase of 250- to 300-fold in neutralizing antibody levels after two rounds of inactivated vaccine administration, proving greater efficacy in using a combination of different types of vaccines to enhance effects.

Taking the CanSinoBIO's aerosolized inhaled adenovirus type-5 vector-based COVID-19 vaccine (Ad5-nCoV) as a booster shot after completing two doses of inactivated vaccine shots for half a year is proven to be safe and significantly more immunogenic than taking an inactivated vaccine as a booster, said Zhu Tao, co-founder and chief scientific officer of the  CanSinoBIO, at a recent industrial conference.

In contrast, neutralizing antibodies can increase by only 30 times if taking an inactivated vaccine as a booster after two inactivated vaccine shots. 

Zhu cited a previous study conducted in Turkey whose data showed a booster dose of the mRNA vaccine widely used in Western countries for people administered along with two inactivated doses can increase the neutralizing antibodies by about 25 times as compared with a booster dose of the inactivated vaccine again.

These clinical trials suggested that a heterologous prime-boost regimen can increase the breadth, intensity and duration of the immune response, more than a homogeneous booster shot. 

US researchers previously conducted clinical trials on a heterologous booster shot regimen with three approved vaccines – one adenovirus-based vaccine by Johnson & Johnson and two mRNA vaccines by Moderna and Pfizer. The results similarly showed that heterologous enhanced immunity had obvious advantages.

The study showed that boosting with any of the three vaccines currently licensed or authorized for emergency use in the US will stimulate an anamnestic response in persons who previously received any of the primary series of any of these vaccines. Homologous boosters increased neutralizing antibody titers 4.2- to 20-fold whereas heterologous boosters increased titers 6.2- to 76-fold, said the research report published on medRvix on October 13. 

So far, at least 13 provinces and regions in China, such as East China's Anhui and Fujian provinces, and Central China's Hubei Province, have initiated programs to enhance residents' immunity against COVID-19.

The latest studies proved that taking the approved Chinese vaccines – inactivated and vector-based ones – in heterologous a booster regime is expectedly the most effective one among all current world-wide regimens using the mRNA vaccine as a booster.

Global Times