Mumbai: Covaxin 1st-dosers remain vulnerable; shortage of particular shots leaves many at risk of infection

A medic administers a dose of Bharat Biotech’s Covaxin at Nair hospital on March 18. Pic/Ashish Raje

Will missing the second shot of Covaxin leave beneficiaries vulnerable to the novel Coronavirus? mid-day answers the question for Mumbaikars who are concerned as there is a serious shortage of Bharat Biotech's vaccine. Beneficiaries who received their first dose are struggling to get their second shot. Experts say following the dosing schedule is important for strong immunity against severe Covid-19 complications.

A health worker receives a shot of Covaxin at JJ hospital on March 3. Pic/Ashish Raje

Besides shortage of the vaccine, vaccination centres have been seeing long queues and there is the problem of non-availability of appointment slots. Covaxin has a two-dose regimen and earlier it was advised to take the second shot 28 days apart. However, the guideline was recently revised, and can now be administered within 28-42 days since taking the first shot. Suchitra Ella, co-founder and joint managing director of Bharat Biotech, informed in a tweet on Sunday.

Speaking with mid-day, Debashish Chakraverty, a Santacruz resident, recollected his 76-year-old mother's struggle in getting her second Covaxin dose, which she did in the nick of time. "She took her first dose on March 18 and it was a smooth and hassle-free process. Getting the second dose was a nightmare. She, along with her friend, literally ran from pillar to post before she got it on April 29," he said.

Chakraverty said since he was recovering from Covid-19 himself, his mother had to go around, enquiring about the availability of the vaccine. "From home, I made 15 calls a day to all the nearby hospitals to enquire about the availability of the second dose. But when that didn't work out, my mother and her friend, also a senior citizen, went to hospitals. I am glad she got it, but instead of 28 days the duration extended to 42 days. The vaccination drive is becoming as big a problem as the disease itself," he added.

Suhasini Kawle, a 74-year-old Parel resident, received her first dose of Covaxin on April 1 and is now anxiously waiting for the second dose. Dr Vijayalaxmi Shinde, consultant clinical microbiologist and infection prevention adviser, Mumbai-Thane area, said duration between two doses are generally 28 days but it may vary as per the efficacy data of that particular vaccine type or the manufacturer.

"Vaccines require doses to be given as per the manufacturer's instructions to elicit a desired immune response. The manufacturers have data and trial studies to associate efficacy with doses and duration of vaccination. First and second doses are planned as per efficacy response generated in data of studies and trials conducted considering different parameters of studies," said Dr Shinde. She said it is important to follow the instructions of the vaccine manufacturer in case the advised duration has lapsed.

Take second dose on time

Explaining what happens if the deadline for the second dose is missed, Dr Ravi Wankhedkar, treasurer of World Medical Association and former national president of Indian Medical Association, said, "Delaying the second dose of Covaxin beyond six weeks [42 days] will increase the vulnerability to Covid-19. The immunity level from the first dose needs a booster of the second dose to develop near-complete immunity. A person who takes the first dose and delays the second one will have a false sense of security and will not follow Covid-19 appropriate behaviour and contract the virus. Hence, the government should prioritise administering the second dose."

Dr Shinde, explaining the importance of vaccination, said it reduces the risk of getting a disease by working with your body's natural defences to build protection. "When you get a vaccine, your immune system responds. Vaccines are also critical to the prevention and control of outbreaks of infectious diseases."

"Right now, we aren't aware when fresh Covaxin will come. We are getting Covishield tonight or by Wednesday morning," Dr Mangala Gomare, executive health officer of the BMC, told mid-day on Tuesday evening.

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Gap in days between the two doses of Covaxin