Thailand’s Nasal COVID-19 Spray Vaccines Set To Start Human Trials

Thailand will start human trials for two nasal coronavirus spray vaccines later this year after getting promising results in mice trials.

On Wednesday, deputy government spokeswoman Ratchada Thanadirek said such vaccines had been developed by the National Center for Genetic Engineering and Biotechnology.

They are based on adenovirus and influenza, the government official said.

After successful results in mice trials, the first phase of human trials should start later this year, she said.

Nasal spray vaccines must be approved by Thailand’s food and drug regulator for their human trial phases, Ratchada added.

She also explained that trials would also test protection against the most contagious Delta variant.

The second phase is scheduled for March 2022, with a production target for wider use expected to start a few months later if good results are achieved, she stated.

The lining of the nose had been identified as a key entry point for the novel coronavirus.

Since then, experts in several countries have conducted research to develop nasal sprays to help prevent and treat Covid-19.

In another development, other locally made vaccines are due to start the second-phase human trials this month.

Homegrown vaccines from Thailand include Chulalongkorn University’s mRNA vaccine and an inactivated virus developed by Mahidol University.

Health officials rolled out a mass vaccination campaign based on the Sinovac, Sinopharm, and AstraZeneca vaccines.

The government has also administered some Pfizer/BioNTech shots as booster vaccines for front-line medical workers.

Veterinary Health Innovation and Management Research Group’s director Dr. Anan Jongkaewwattana say those shots are administered via intramuscular injections to stimulate antibodies in the bloodstream.

However, they are not effective enough to protect the nasal passage and prevent the virus from invading the body as it enters the body through the respiratory system.

But the nasal spray vaccine can produce antibodies in the mucous lining of the nasal passage, where the virus usually takes root.

Dr. Anan stated that nasal spray vaccines were not new, adding that a nasal influenza spray vaccine has been on the market since 2003.