NASAL VACCINE
1. Context
Bharat Biotech’s COVID-19 recombinant nasal vaccine has been approved by the Ministry of Health’s Central Drugs Standard Control Organisation for primary immunisation of those aged 18 years and above in emergencies
2. What is a nasal vaccine
Vaccines are usually given through different routes, with the most common being injectable shots delivered into the muscles (intramuscular) or the tissue just between the skin and the muscles (subcutaneous).
There are also other routes of delivery, especially in some vaccines for infants, that include administering the liquid solution orally instead of injecting
In the intranasal route, the vaccine is sprayed into the nostrils and inhaled.
Many viruses, including the coronavirus, enter the body through mucosa-wet, squishy tissues that line the nose, mouth, lungs and digestive tract triggering a unique immune response from cells and molecules there.
Image Source: Science Direct
3. How does a nasal vaccine work
In the case of both delivery routes, vaccines trigger a response in the blood.
B cells, for example, would churn out antibodies including a particularly potent disease-fighter called IgG to roam the body in search of the virus
Other cells, called T cells, would either help B cells produce antibodies or seek out and destroy the infected cells.
But vaccines that are injected through the nose or mouth also tap into another set of immune cells that hang around mucosal tissues.
The B cells that reside there can make another type of antibody, called IgA, which plays a key role in destroying airway pathogens.
In addition, the T cells that are residing nearby will be able to memorise the pathogens that they encountered and will lifelong scout the areas where these were first encountered.
4. Importance of nasal vaccine
These vaccines aim to overcome potential difficulties with mass vaccination and reduce the cost by doing away with the need for needles and syringes
Intranasal vaccines are also expected to cut down on the dependence on various trained personnel to administer the vaccine
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For Prelims: T cells, B cells, antibodies
For Mains:
1. What is the nasal vaccine? How will it help combat Covid-19
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