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Nasal spray COVID-19 vaccine vs injection: Which one should you opt for?

Nasal spray COVID-19 vaccine vs injection: Which one should you opt for?
Putting a vaccine directly into the nose may offer another kind of immunity, besides systemic immunity.

China has approved its first nasal spray COVID-19 vaccine for trials. Researchers say nasal vaccination may provide double protection against influenza viruses and the novel coronavirus.

Written by Longjam Dineshwori |Updated : September 11, 2020 10:19 AM IST

China is one of the front-runners in the global race to develop a COVID-19 vaccine. Around eight different vaccines are said to be under clinical trials, but none have so far been approved for the market. Russia registered its first vaccine candidate, Sputnik V, developed by Moscow's Gamaleya Institute, in August. But China claimed that it has been administering its domestically-developed COVID-19 vaccines to a broad range of people, including medical workers, the armed forces, and employees of companies who are working overseas, since July 22. Now, the country has approved its first nasal spray COVID-19 vaccine for clinical trials. Phase I clinical trials of the nasal spray vaccine is expected to start in November by recruiting 100 volunteers.

How does the nasal spray vaccine work?

The vaccine is developed jointly by researchers from the University of Hong Kong, Xiamen University and Beijing Wantai Biological Pharmacy. It is the only vaccine of its type approved by China's National Medical Products Administration, Chinese media reported.

According to the researchers, the vaccine stimulates the natural infection pathway of respiratory viruses to activate the immune response. The nasal spray vaccination could provide double protection against influenza and the novel coronavirus if it also contains influenza viruses including H1N1, H3N2 and B, they said. However, it would take at least another year to finish the three clinical trials, Yuen Kwok-yung, a microbiologist from the University of Hong Kong, told Chinese media.

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Nasal vaccination may offer better protection against coronavirus

As per the researchers, a nasal spray vaccination is easier to administer and mass-produce and distribute compared to injections. This is because nasal spray vaccination adopts the mature influenza vaccine production technology, i.e. it uses live attenuated influenza vaccine.

China also uses four other technical routes to develop the coronavirus vaccines including inactivated vaccines, adenoviral vector-based vaccines, and DNA and mRNA vaccines.

The nasal spray vaccine may not cause systemic side effects, but it may have an effect on the respiratory system. However, the developers do not expect any serious side effects except for minor nasal obstruction or rhinorrhea.

Can nasal spray vaccinations generate immunity against coronavirus longer than injected vaccines? This is something the researchers are not yet clear about.

Most vaccine developers believe that an injection into muscle tends to give the strongest immune response. However, a respiratory virus like a coronavirus typically starts infecting the nose or throat first, and the infection can stay there before the systemic immunity kicks in. Therefore, while injected vaccines might protect people from getting terribly sick, they still might have a virus in their nose that could spread to others. Putting a vaccine directly into the nose may offer another kind of immunity, besides systemic immunity. The nasal spray could stop the virus to start an infection inside your nasal passages and spread to others.

Phase-3 trials of Sinovac's Covid-19 vaccine shows promising result

Brazil Governor Jo o D ria on Wednesday informed media persons that phase-3 trials of the vaccine developed by China's Sinovac have shown positive results in the participants. He also hinted that the vaccine may be made available in the country as early as December

According to D ria, phase-2 trials of the potential vaccine had built 98 percent of immune responses in the elderly. The trials that included 9,000 people were carried out in Sao Paulo by the Butantan Institute. Brazil is planning to carry out the trials for Russia's vaccine Sputnik V next year. The country had to pause another trial for the vaccine developed by AstraZeneca after a participant in Britain demonstrated an unexplained illness, according to media reports.