Production line of an aerosolized adenovirus type-5 vector-based COVID-19 vaccine (Ad5-nCoV) developed by CanSino Biologics Photo: Courtesy of CanSino

 Shanghai on Tuesday became the first city in China to provide a domestically developed aerosolized adenovirus type-5 vector-based COVID-19 vaccine (Ad5-nCoV) for booster shots while the country keeps exploring new and better strategies of mass vaccination in face of the rapidly mutating virus.
The Shanghai municipal government announced on its WeChat account that reservations had opened and the vaccination would kick off on Wednesday.

The reservations are open to all local adults who have received two doses of inactivated vaccines produced by Sinopharm and Sinovac Biotech or one shot of CanSino Biologics (CanSinoBIO)'s intramuscular Ad5-nCoV more than six months ago, according to the announcement.

Receiving a booster shot is an effective method to enhance the protection effectiveness and prolong the protection duration of vaccines, the Shanghai government noted in the announcement. According to the government's announcement on Tuesday, 23 million Shanghai residents had been fully vaccinated against COVID-19, and more than 12 million of them had received booster shots.

Chinese vaccine manufacturer CanSinoBIO confirmed with the Global Times on Tuesday that the aerosolized Ad5-nCoV vaccine to be available in Shanghai is the one jointly developed by CanSinoBIO and researchers from the Institute of Military Medicine under the Academy of Military Sciences led by Chen Wei.

It is the world's first aerosolized COVID-19 vaccine and it was approved by Chinese national authorities for emergency use as a booster in September, according to the company.

An aerosolized adenovirus type-5 vector-based COVID-19 vaccine (Ad5-nCoV) developed by CanSino Biologics Photo: website of CanSino

 According to a video released by Shanghai media, the aerosolized vaccine is contained in a sipping cup like the ones used to contain bubble tea. To get vaccinated, people only need to bite the mouth on top of the cup and take a deep breath to bring in the gas and hold their breath for five seconds.

The design is inspired by the way that people drink coffee, but instead of being drunk into the stomach, the aerosolized vaccine will be inhaled into the respiratory tract and lungs, the Global Times learned from CanSinoBIO.

Research shows that respiratory droplets and close contact transmission are still the main transmission routes of the SARS-CoV-2. The aerosolized vaccine could stimulate immunity on the respiratory mucosa, the "first point of contact" between the body and the virus, which is like putting an "invisible mask" on the inhaler, the company said in a statement to the Global Times.

Clinical trials proved that the aerosolized vaccine is safe and highly immunogenic in inhalers, according to the company.

Studies showed that six months after inoculation with two doses of inactivated vaccine, the level of neutralizing antibodies against the Omicron mutant strain in people receiving the aerosolized Ad5-nCoV as booster shots is 14 times than that of those receiving homologous boosters, and six times than that of people receiving intramuscular Ad5-nCoV, the company said.

The aerosolized Ad5-nCoV has the advantages of stable storage and transportation under temperatures of 2-8C, which can facilitate vaccination of large-scale risk groups more efficiently and improve vaccine accessibility and affordability in developing countries, the company noted.

Shanghai's move comes as China keeps exploring new and better strategies of mass vaccination in the face of the rapidly mutating virus while upholding a dynamic-zero COVID-19 policy to protect the lives and safety of the Chinese people to the utmost amid nationwide sporadic cases.

According to the National Health Commission, China had 3,654 confirmed cases with 468,367 people under medical observation as of Monday.

As of the same day, nearly 3.5 billion shots of COVID-19 vaccines had been administered in China, the commission said.

According to media reports, more than 1.3 billion people in China had been fully vaccinated and the vaccination rate exceeded 90 percent.

As to the question on whether such a high vaccination rate indicates that it is safe for China to relax epidemic restrictions, Chinese officials and experts warned about rapidly emerging mutations and kept calling for better vaccines and drugs as well as vaccination strategies to provide better protection for the people.

Gao Fu, former head of the Chinese Center for Disease Control and Prevention, urged people to get booster shots as soon as possible as the mutations have weakened the vaccines' efficacy in preventing infection, disease and transmission.

As to whether China will provide a fourth shot to the public, Gao said the national authorities would make a decision based on further research and study.

Health experts said that the current vaccines used in China are all developed based on the original variant. They believe that China will provide a second round of booster shots specifically developed for Omicron before relaxing epidemic restrictions.

The Global Times learned that several Chinese vaccine makers including Sinopharm, Sinovac and CanSinoBIO have made progress on Omicron-specific vaccines. Sinovac said in September that it was expecting to submit safety and immunogenicity data from the clinical trials for its Omicron-specific candidate to related national authorities and apply for emergency use.