COVID-19: Why nasally administered vaccine experiments are gaining ground among drug makers

Pune-based Serum Institute of India announced early this week that it will manufacture US-based Codagenix's intranasal live-attenuated (weakened) COVID-19 vaccine candidate.

Serum had received regulatory approval from the Review Committee on Genetic Manipulation (RCGM) of the Department of Biotechnology (DBT).

Serum will supply the vaccine for large-scale safety and efficacy studies even as it prepares to meet global vaccine supply requirements.

The pre-clinical testing of a single, intranasal dose of the vaccine, called CDX-005, in animals has yielded encouraging safety and efficacy signals, Codagenix and Serum said in a joint statement.

Plans are under way to begin human testing or Phase I trial in the UK before the end of 2020.

Serum has company

Another Indian vaccine maker, Bharat Biotech, on Wednesday announced that it had entered into a licensing agreement with Washington University School of Medicine in St Louis for a novel chimpanzee-adenovirus, single dose intranasal vaccine for COVID-19.

While the Phase I trials will take place in St Louis University’s Vaccine & Treatment Evaluation Unit, Bharat Biotech, upon obtaining regulatory approval, will pursue further stages of clinical trials in India, and undertake large-scale manufacture of the vaccine at its GMP facility in Genome Valley, Hyderabad.

Interestingly, the intranasal vaccine of both Serum and Bharat Biotech requires only a single dose, compared to two doses other vaccines might need.

What is intranasal vaccine?

Intranasal vaccine is administered through nose, in contrast to most vaccines that are given as injections, with the exception of polio vaccine, which is delivered orally.

AstraZeneca’s FluMist is the only nasal spray vaccine against H1N1 Influenza or a flu that’s approved in the US, Canada and Europe so far. FluMist vaccine contains four different variants of weakened or live- attenuated flu viruses.

Is intranasal vaccine effective?

Many viruses, including Coronavirus, infect through mucosa, the moist tissue found in the nose, mouth, lungs and digestive tracts. Unlike other COVID-19 vaccines in development, intranasal vaccine is delivered at the infection site , i.e., the nose and lungs to stop infection.

Researchers in Washington University School of Medicine, who developed the vaccine, in their animal studies on mice, compared the intranasal vaccine to vaccine given through intramuscular injection.

They found that while the injection induced an immune response that prevented pneumonia, it did not prevent infection in the nose and lungs. In contrast, the nasal delivery route prevented infection in both the upper and lower respiratory tracts — the nose and lungs — suggesting that vaccinated individuals would not spread the virus or develop infections elsewhere in the body.

The study was published in Cell, the peer-reviewed scientific journal. The researchers said that they will test the vaccine on non-human primates or monkeys for efficacy.

Why companies are focusing on intranasal vaccine?

There are plenty of advantages. An intranasal vaccine is simple and efficient to administer. It doesn't require the use of medical consumables such as needles and syringes, thus significantly lowering the overall cost of a vaccination drive. It is also convenient for self-administration.

What do experts say?

Experts like Dr Gagandeep Kang have a word of caution on nasal vaccines.

“Approved Influenza vaccines can be given by injection or nasally. Usually, mucosally delivered vaccines will have somewhat lower immune response," Dr Kang told Moneycontrol.

Kang is the country's leading expert on vaccines and Professor at the Department of Gastrointestinal Sciences at Christian Medical College, Vellore.

Another expert at a vaccine company, who didn't want to be named, said the intranasal flu vaccines may have better safety profile and are found to be more effective in children compared to adults.