New Delhi: As nasal vaccines roll out and confusion cropped up about people eligible for it, experts have now cleared the air saying that nasal vaccine is recommended as "first booster" and that people who have already received their preacutionary dose need not take the nasal vaccine. 


"It (nasal vaccine) is recommended as the first booster. For example, if a person has already received a precaution dose, it is not recommended for that person. It is for those who have not yet taken a precaution dose," Dr NK Arora, who has been closely involved with the rollout of vaccines from the onset of the pandemic, told NDTV.


Amid a sharp uptick in Covid-19 cases globally, especially in neighbouring China, the government on Friday approved Bharat Biotech's intranasal vaccine as a booster dose for those aged 18 years and above. 


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The vaccine, named iNCOVACC, had received approval of the drugs regulator in November for restricted use in an emergency situation as a heterologous booster dose. Heterologous booster means a person can be administered a different vaccine as a third shot from the one that he/she received as the primary dose.


The two-drop needle-free nasal vaccine is likely to be introduced on the Co-WIN platform from Friday evening and eligible people can book their shot from the mobile application or website.


The nasal vaccine will be available only at private hospitals as of now.


iNCOVACC is stable at 2-8 degrees Celsius for easy storage and distribution.


It can only be taken as a precaution or third dose by adults who have been vaccinated with two doses of either Covishield or Covaxin.


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In this case, the vaccine dose is given via nose, rather than orally or through the arm. The target is to deliver the dose into the respiratory pathways. The vaccine is either injected through a specific nasal spray.


Nasal vaccines are easy to administer and builds up immune barriers in the respiratory tract through which respiratory viruses enter the body.


It must be noted that the respiratory tract epithelium is the key entry point for the novel coronavirus.
iNCOVACC is a recombinant replication deficient adenovirus vectored vaccine with a pre-fusion stabilised spike protein.