By Dr. Bushra Saleem Shaikh*
MUMBAI—A vaccine is a biological preparation that provides active acquired immunity to a disease. Vaccines are our tool to fight infectious diseases by providing herd immunity to the population. What is herd immunity you ask, well when most of a population is immune to an infectious disease, this provides indirect protection— or population immunity (also called herd immunity or herd protection)—to those who are not immune to the disease. The entire aim of vaccination is to attain herd immunity. Let us objectively look at different aspects of vaccination in India and analyse the role it would play in our fight against covid 19!
Types of covid vaccine available
• Inactivated or killed vaccines- here the pathogen (virus) is weakened and then administered in our body so that our immune system can learn to look for it and generate an immune response upon the natural entry e.g., Covaxin by Bharat biotech.
• Viral vector vaccine- in these types of vaccine we make use of a carrying pot called vectors e.g., Covishield uses chimpanzee adenovirus vectors to carry viral genetic material so as to introduce it into our bodies telling us how does genetic makeup of virus look like, sputnik of Russia uses human adenovirus.
• mRNA vaccines- a part of RNA (the genetic material of virus) is taken from spike protein of covid virus to make a vaccine e.g., Pfizer and Moderna covid 19 vaccines.
Side effects of vaccines
A good vaccine when administered brings about a vaccine reaction in the milder form of actual disease, which tells us that vaccine was able to generate a good immunogenic response. So the fever and body ache after the vaccine isn’t actually a side effect but a desired effect, local mild side effects include pain at the side of vaccination or an abscess (puss pocket) at worst. When we talk of side effects a rare chance of anaphylaxis (severe allergic reaction to vaccination) does exist, but anaphylaxis is not specific to covid vaccine alone and can occur virtually with any other vaccine, medicine, or even food.
Anaphylaxis is an idiosyncrasy that cannot be predicted. Other major but rare side effects include an increase in clotting disorders and neuroinflammatory conditions (inflammation of nerves). But it should be bored in mind that we are still in the process to acquire relevant data on the issue and such occurrences are extremely rare. Such rare occurrences are true for any vaccine and a lot of infectious diseases such as polio, mumps, measles, or rubella were fought off by vaccines having similar side effects. Now the question arises, Are some people or people with pre-existing condition more prone to side effects than other? Well, we still lack relevant clinical data in the matter, but studies do suggest idiosyncrasy, your immune reaction may have a unique varied response to disease.
Should people with co-morbidities (like diabetes hypertension or kidney diseases) get vaccinated?
Absolutely yes! People with co-morbidities require more protection and it’s a part of the reason why the government opted to vaccinate this population first. But should an immunocompromised patient get vaccinated? Again, absolutely yes! but the effectivity of vaccine on them is less than that of the normal population as vaccine depends on a good immune response. Immunocompromised people include people with HIV, patients on long-term steroids, patients with genetic disorders, and those receiving chemotherapy. The only contraindication to vaccination is anaphylaxis to 1st dose or severe side effects after the first dose (like clotting disorder).
In conclusion entire population should get vaccinated! Now the important question that we all have been wondering about Covishield or Covaxin???
Covaxin required two doses 4 weeks apart and interim data shows 80% efficacy after 6 weeks of complete immunization whereas Covishield required two doses 6-8 weeks apart but the first dose provides 70% efficacy and about 90% after 3 months of complete vaccination. To answer objectively one should get vaccinated with the available option in view of the shortage of vaccine.
Why do people test positive after getting vaccinated if it has such good efficacy?
Well, it is because vaccine takes time to build immunity, we cannot expect 100% efficacy moments after the first dose, it does take time for our immune system to be able to create a memory of what virus looks like and be ready with antibodies. Also, the crowding at the vaccination center adds to the cases just after vaccination.
What happens if we are able to get only one dose due to a shortage of vaccines?
Wait up till your turn arrives, as the first dose does provide some immunity it should hold up well. WHO recommends that vaccination can be followed up within a span of 6months, if the duration happens to exceed 6month then you may need to take the 1st dose again.
Now, what if you get infected after 1st dose?
Even if you get infected after vaccinations cases are usually asymptomatic, milder, or with less lung involvements. But do not skip the second dose, take Covaxin after 4 weeks of recovery and Covishield after 8-12 weeks. The vaccine after natural infection will act as a booster and provide a better protection
Will vaccine protect against new strains?
We still have no clear data on the topic, but it is widely speculated that vaccines should work against the new stain providing partial if not complete immunity against it. And so far, a milder form of the disease is observed in vaccinated individuals.
What provides better immunity vaccine or natural infection or if people who got infected should get vaccinated??
Vaccine plus infection provides the best protection that we know of, hence people who were infected should get vaccinated as it would act as a booster and give better protection. But if we are to compare natural infection provides better immunity.
Can we stop taking precautions after vaccination?
While a COVID-19 vaccine will protect you from serious illness and death, we still don’t know the extent to which it keeps you from being infected and passing the virus on to others. To help keep others safe, continue to maintain
at least a 1-meter distance from others, cover a cough or sneeze in your elbow, clean your hands frequently and wear a mask, particularly in enclosed, crowded, or poorly ventilated spaces {WHO}. So as the caller tunes say “dawai bhi aur kadai bhi”.
Can vaccines cause a false positive RT PCR or antigen test?
No, the COVID-19 vaccine will not cause a positive test result for a COVID-19 PCR or antigen laboratory test. This is because the tests check for active disease and not whether an individual is immune or not. However, because the COVID-19 vaccine prompts an immune response, it may be possible to test positive in an antibody (serology) test that measures COVID-19 immunity in an individual.
So, the question arises, can vaccination help us end the pandemic? The end of a pandemic depends on a number of factors like the efficacy of the vaccine, the number of people vaccinated, the new variants, and also the containment of clusters of outbreaks. The Spanish flu (last viral) pandemic went on at a peak for about 2 years then had smaller outbreaks for about 7-8 years before coming to a halt. But vaccination provides us hope that like various other communicable diseases that we had battled in the past like mumps, measles, polio, and the great smallpox, vaccination if carried out with efficiency can bring this mighty monster to the end of its glory. We also need to adapt to a new lifestyle of social distancing, mask and clean hands along with vaccination if we want to conquer the virus.
* Dr. Bushra Saleem Shaikh is ICU Resident Doctor at Seven Hills Hospital, Mumbai. She can be contacted at [email protected]
Very good and useful work. Continue with your efforts.