1. What are the different types of Corona vaccines likely to be available for use in the near future?
* mRNA vaccine (Pfizer and Moderna)
Consists of messenger RNA molecules of the virus which code for parts of the target pathogen that are recognised by our immune system (Antigens). Inside our body's cells, the RNA molecules are converted into antigens which are then detected by our immune cells to produce antibodies.
* Vector vaccine (Oxford Astra Zenica - Serum Institute of India)
Covishield viruses that have been modified to contain antigens from the target pathogen. The modified viruses act as delivery systems that display the antigens from the target pathogen. The modified viruses act as delivery systems that display the antigens to our immune cells. Replicatingviral vectors make extra copies of themselves in our body's cells. Non-replicating viral vectors do not. Chimpanzee adenovirus is the vector used to deliver the corona virus antigen in the SII vaccine covishield.
* Inactivated vaccine (Bharat Biotech India Ltd). Covaxin and the Sputnik V from Russia's Gamaleya Research Institute, marketed by Dr Reddy's lab in India
Consist of inactivated versions of the virus. These are detected by our immune cells but cannot cause illness.
2. How effective are those vaccines?
* The Oxford Astra Serum Institute vaccine has demonstrated efficacy of 70.4% against symptomatic Covid-19 and 100% efficacy against hospitalisation due to severe Covid-19.
* The Pfizer vaccine has been demonstrated to have 95% efficacy.
* The Sputnik vaccine has demonstrated 92% efficacy.
3. Who can be administered the vaccine?
The 4 vaccines mentioned have undergone immunogenicity, efficacy and safety trials in 18 years and above and hence will be allowed to be used in adults under "Emergency Use Authorisation". Trials are underway for age group 12-18 and in due course of time, the vaccines may be allowed to be used in this age group.
4. Will all the 4 vaccines be made available and will everyone have access to all the vaccines?
The Oxford Astra-Serum Institute vaccine has applied for EUA and is likely to be made available soon.
The BBIL vaccine is yet to complete the phase 3 trial and submit the trial results for EUA. Sputnik is being tested in India.
Pfizer vaccine may be made available in private sector. Frontline workers, elderly, individuals with comorbidities and then, then other healthy adults will be vaccinated in order of priority.
Neither is any vaccine available nor is it recommended for use in individuals below 18 years of age.
5. Does an individual already suffered need the vaccine?
It is not very clear if a natural infection would protect an individual in the long run. The antibodies developed by the corona infected individual wane over time. In the absence of a direct correlate of protection in the form of antibody titres and considering the cell mediated immunity, waned antibody levels may not mean loss of protection. However, given the huge number of doses required, the individuals who have recovered from Covid 19 will be considered last for vaccination.
6. Can a pregnant lady take the vaccine?
As of date there is no data on safety in pregnant women. Pregnant women were excluded from the trials.
7. Can it be given to immunocompromised individuals?
Yes, the mRNA vaccine and inactivated vaccines are safe and even the adenovirus vector vaccine is safe as the vector is nonreplicating.
8. What is the recommended dose and schedule?
2 doses of 0.5 ml 28 days apart for the Oxford Astra serum vaccine and 2 doses of 0.5 ml 21 days apart for the mRNA vaccine and the Sputnik vaccine.
9. How long does it take for the vaccine to develop antibodies (protection)?
Generally, it takes two weeks for the antibody response. The mRNA vaccine of Pfizer has demonstrated response as early as 10 days after the 1st dose.
10. What are the cold chain requirements for these vaccines?
The Oxford Astra serum vaccine and Sputnik can be stored at 2 to 8 degrees. However the mRNA vaccines need to be stored at -70 degrees. It can be kept at -20 degrees for a week and on field retains viability for a day at 2 to 8 degrees.
Source. Excerpted from the compilation by IAP Navi Mumbai.
Tailpiece.
Got up at 6, the chores and was ready by a half past 9.
The Kudumbasree's scavenging team had come and collected the dry waste - plastic and empty milk covers - as part of their monthly beat.
It was a rather quiet Monday!
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