- It is important to take the second dose of a vaccine: Dr Swaminathan, WHO
- Second dose can be taken a few days early or later from the schedule: WHO
- No untoward event following vaccination has been reported so far: WHO
New Delhi: In the fight against the Coronavirus pandemic, countries across the world have started vaccinating their citizens, healthcare workers and essential workers. India too kick started its vaccination drive on January 16 with Oxford-AstraZeneca’s Covishield and Bharat Biotech’s Covaxin. The country has already vaccinated 1.26 crore healthcare and frontline workers and the second phase of the coronavirus vaccination drive will begin March 1, with priority given to people over 60 and those over 45 with co-morbidities. As the COVID-19 vaccination drive expands, the World Health Organisation’s (WHO) Chief Scientist Dr Soumya Swaminathan answers key questions related to COVID-19 vaccines and dosage.
As part of WHO’s conversations in science, Dr Swaminathan informed that multiple vaccines are being developed and every vaccine has a different dosing schedule. Majority of the vaccines currently being manufactured in the world are two dose vaccines and usually, the two doses are given at a gap of three to four weeks.
But there is some data from some vaccines like the AstraZeneca vaccine, where delaying the second dose up to 12 weeks actually gives a better immune boost, said Dr Swaminathan.
Further when asked what happens if someone delays or misses the second dose of the vaccine, Dr Swaminathan noted that it is important to take the second dose; it doesn’t matter if it’s early by a few days or late by a few days or even a couple of weeks.
It’s important to go back and get that second dose because the first dose actually presents this new antigen to the immune system to prime it. And the second dose is the one that really gives a boost to the immune system so that the antibody response, as well as T cell mediated response, they are very strong and they also develop a memory response, which then lasts for a long time, so that when the body sees this antigen again, this virus protein again, it knows that it needs to react quickly, explained Dr Swaminathan.
In India, the two COVID-19 vaccines that have got the emergency use license are two dose vaccines and are given at a gap of 28 days. The Ministry of Health and Family Welfare recommends taking the two doses of the same vaccine. The guideline is in line with WHO’s policy advice. Talking more about mixing the two vaccines, Dr Swaminathan said,
The science is changing and evolving and the knowledge base is growing. There are now clinical trials ongoing in some countries that are looking at interchangeability, which means the first dose with one vaccine and the second dose with a different vaccine, maybe even a different platform vaccine. And immunologically, there are reasons why this would make sense. However, at the present time, there isn’t enough data for us to recommend this type of interchangeable two dose schedules.
Are COVID-19 Vaccines Safe?
Usually, it takes years to develop a vaccine that is both safe and efficacious as any new vaccine or drug has to go through multiple stages of trials. However, scientists across the world have developed vaccines against COVID-19 in a record time of less than a year. The speed with which vaccines have been manufactured often raises questions over their efficacy. Clearing all apprehensions, Dr Swaminathan detailed the regular vaccine development process and how it has been altered during a pandemic. She said,
Vaccine development is a complex process, and it goes through different phases, starting from animal studies, through the phases of clinical trials in humans. And the last phase, Phase III, is normally done in several thousand individuals, tens of thousands of individuals. Half are given the placebo, half are given the vaccine. They are followed up over a period of time, usually, it’s a couple of years and then we assess the efficacy and the safety of the vaccine. Now, because of the pandemic and the need to get these vaccines out quickly to save lives, the duration of follow up has been a couple of months rather than years, and emergency use authorisations have been given to these vaccines, which means that they are still under observation. There are still systems in place in countries that are following up people that are recording and reporting any serious adverse events or other events.
Dr Swaminathan informed that the WHO has a pharmacovigilance system under which adverse events are constantly monitored. She added that so far no untoward event resulting from vaccination has been reported but WHO will continue to be vigilant and as and when any evidence of a relationship between a vaccine and side effect is developed, countries will be informed.
NDTV – Dettol Banega Swasth India campaign is an extension of the five-year-old Banega Swachh India initiative helmed by Campaign Ambassador Amitabh Bachchan. It aims to spread awareness about critical health issues facing the country. In wake of the current COVID-19 pandemic, the need for WASH (Water, Sanitation and Hygiene) is reaffirmed as handwashing is one of the ways to prevent Coronavirus infection and other diseases. The campaign highlights the importance of nutrition and healthcare for women and children to prevent maternal and child mortality, fight malnutrition, stunting, wasting, anaemia and disease prevention through vaccines. Importance of programmes like Public Distribution System (PDS), Mid-day Meal Scheme, POSHAN Abhiyan and the role of Aganwadis and ASHA workers are also covered. Only a Swachh or clean India where toilets are used and open defecation free (ODF) status achieved as part of the Swachh Bharat Abhiyan launched by Prime Minister Narendra Modi in 2014, can eradicate diseases like diahorrea and become a Swasth or healthy India. The campaign will continue to cover issues like air pollution, waste management, plastic ban, manual scavenging and sanitation workers and menstrual hygiene.