Important Updates on available vaccines against covid and immunisation!


Recent resurgence of SARS COV 2 –   Covid 19 disease in our country led by Second rung cities of Maharashtra , closely following worldwide rising trend of new virus variants such as B.1.1.7 ,  B .1.351 and P.1 representing United Kingdom, South Africa and Brazil origin. Such variants suggest critical mutations which has the potential to change the course of the disease. These forms  suggest origin of much predicted second wave of the mayhem in our country too . It has started ringing alarm bells and therefore needs re-emphasis on the value of vaccination as the only definitive answer in limiting the impact of this scourge. Fortunately in our country we have only very limited impact of South Africa variant which is the most sinister of the three.

Human body is inhabited and surrounded by trillions of microbes and some of which are useful but may turn harmful if our immune system is weakened and microbes make it’s entry easy mainly through breathing and food or water.

Co – morbidities ( Associated  common diseases) such as Diabetes ,high blood pressure , hypothyroidism  and above all Obesity , or even natural ageing , all can weaken our inbuilt immunity.

Some of these microbes are viruses which have jumped from animals , are grouped as Zoonotic viruses , such as SARS COV 2, a novel corona virus leading to Covid 19 , which has been altogether foreign to our immune system and therefore unable to mount trained  attack to thwart it’s entry into our body in the absence of natural and  organism specific adaptive immunity  . Only way to disallow it’s entry into our body is to vaccinate against this novel life threatening virus with the help of appropriate vaccine which we have started using only since January 16 .

History of immunisation by vaccine is a proven  science without an iota of doubt . This started in modern times by Edward Jenner who found vaccination against deadly Small Pox virus in nineteenth century as a definitive answer . Currently we have very potent vaccines for a number of very serious diseases with unqualified  success such as poliomyelitis, Rabies, mumps, measles etc . The hesitation against vaccination must go away once for all and we must volunteer for ourselves for vaccination at the earliest, as and when we become eligible.

It is worthwhile periodically revisiting the present state of immunisation against SARS COV 2 – disease.


The following are few points worth noting.

 1.       All must take vaccine without any delay or doubt in order to safeguard his or own self and the society at large to attain personal safety and much desired ‘herd immunity ‘-  the desired protection level of immunity for the society in general , at the earliest. This is the only effective solution as preventive therapy and nothing else !

2.       Both Covishield ( Oxford -AstraZenica )and Covaxin ( ICMR- Bharat biotech) are good enough to produce adequate immunity  .  Controversy surrounding Covishield have gradually subsided and people should feel reassured .

3.       Both vaccines require two doses. Covaxin needs to be repeated after four weeks where as covishield may have to be delayed upto twelve weeks for better immunity as suggested recently . However ,one should give precedence to government of India advisory at a given point of time and situation .

4.       Some amount of pain is expected following vaccination at the site of injection .  However, this pain decreases significantly within days. Only very few have systemic reactions such as fever , malaise or loss of well being which is probably being experienced less in covaxin.

5.       Those who are suffering from disease which necessitates taking anti – coagulants ( warfarin like drugs ) must consult their doctors before going for vaccination. Anti platelets such as aspirin and clopidogrel are not contraindications to vaccination . However , in case of doubt it is always better to ask your doctor or the vaccine manufacturers .

6.       These reactions generally subside within a few days only but occasionally there may be manifestation of acquired covid infection contracted days before vaccination or within first few days following vaccination , more so if history of exposure to patients are available .This is unrelated to vaccine administration.

7.       This fever even if with RTPCR positivity for SARS COV 2 virus ,suggesting covid disease, is not a sign of ineffective vaccination as  minimum effective neutralising antibodies take time to reach to a minimum protection level,   which is three to four weeks after administration of vaccine “covishield “and  probably longer for “Covaxin”.   Long term protection is through lymphocyte T cell derived adaptive immunity which as suggested may take longer time but such immunity is far more effective in thwarting any such attack by the virus.

8.       As cases of infection have been increasing incessantly in last few weeks all around our country , setting each day for a newer higher number, serious attention and continuing practice towards using mask,preferably a double mask , once one is outside their homes and more so if in public places . We should also maintain as much distance as possible between people , and meeting as fewer people as possible and that too only in open and fully ventilated places , are gold standard  protection measures .  Washing hands frequently , has been old good practice and should be adopted permanently in our future routine and social behaviour as it cuts down on several other common infections in day today life . There are reports that many such oral – faecal entry associated diseases like Gastro – enteritis , Typhoid fever etc . , have concurrently come down significantly in last one year , most likely due to regular hand washing and increased cleaning practices.

9.       Two or more fully vaccinated people alone can meet without mask and distancing ,  but only if there are no unvaccinated in the group . It is proper to take precautions when unvaccinated people are part of the group even if unvaccinated people are small in number .

10.     One should not forget that available vaccines in India are successful to immunise only in 60 to 80% of those amongst vaccinated, making it clear that 20-40% will remain un -immunised and therefore shall remain susceptible to infection even after completion of vaccination .

11.     Most studies indicate that even after two weeks following two doses of vaccines , you are protected from only serious forms  of covid 19 disease and possible death  . Covaxin may be better in fighting emerging mutants as it’s a whole virus in killed form .

12.     Mild and moderate infections by SARS COV 2 virus may continue even in those who are vaccinated and therefore full protection measures must continue for more time till herd immunity in the population is achieved and people are vaccinated globally (in this highly connected world ) in larger number and therefore will require longer time to achieve !

13.     Those who have recovered from SARS COV 2 -covid disease should also take at least one shot of vaccine without delay. In case of doubt one can measure neutralising antibody titre value which is a guide for protection level.

14.     The  story of  new mutant forms such as those emerging from South Africa or Brazil appear to be even more scary and therefore strict surveillance of international travel is extremely important . please never let your guards  off as the pandemic is far from over!!

15.     The impact of vaccination is already visible in countries where vaccine campaigns are at advanced stage as Israel , South Korea. We need to expedite the process at break neck speed to achieve the desired result at the earliest

16.     Relaxation of eligibility criteria for vaccination down to 45 years from 1st April, is very welcome news. Very soon we are going to have a few more vaccines such as Russian vaccine’ Sputnik by Reddy lab ‘  and  one from Johnson and Johnson available in our country , making the process of achieving the much desired herd immunity faster .


The author is Former Professor and Head, Department of medicine, RIMS , Ranchi, Jharkhand.


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