The first dose of the COVID-19 vaccine does not produce protective immunity, but prepares the immune system to fight against COVID-19 infection, said All India Institute Of Medical Sciences (AIIMS) Director Dr Randeep Guleria said.
The second dose triggers the immune system to produce a large number of antibodies and gives cell-mediated immunity. It also stimulates memory cells so that the body remembers this infection for the long term and helps produce antibodies quickly in case of reinfection, he added.
Therefore two doses of the vaccine are essential to get maximum protection from COVID-19, Dr Randeep Guleria further said.
Meanwhile, the cumulative number of COVID-19 vaccine doses administered in the country has exceeded 17.52 crore, Union Ministry of Health and Family Welfare said on Wednesday.
A total of 17,52,35,991 vaccine doses have been administered through 25,47,534 sessions, according to the provisional report till 7 am.
These include 95,82,449 healthcare workers (HCWs) who have taken the first dose and 65,39,376 HCWs who have taken the second dose.
Besides, 5,58,83,416 and 78,36,168 beneficiaries aged 45 to 60 years have been administered the first and second dose respectively, while 5,39,59,772 and 1,62,88,176 beneficiaries more than 60 years have taken the first and second dose.
A total of 4,79,282 beneficiaries in the age group of 18-44 years have received their first dose of COVID vaccine in the last 24 hours and cumulatively 30,44,463 across 30 states and UTs since the start of phase-3 of vaccination drive.
The Ministry said more than 24.4 lakh vaccination doses were administered on Tuesday.