Cases of people getting Covid-19 after receiving their full vaccine dose are rare but not unheard of. But before anybody can say ‘why vaccinate?’, it has been pointed out by experts that people who do get infected after two rounds of vaccination normally get very mild symptoms or remain asymptomatic. This, experts say, can be attributed to the vaccine itself, which mostly prevents anything but a mild infection in such cases.
Can You Get Covid-19 After Full Vaccination?
To be sure, cases of people getting Covid after completing their vaccination are few and far between. Such cases are called ‘breakthrough’ infections as the disease is seen as penetrating through the antibody shield provided by the vaccine. According to official data released in the middle of May, 0.13% of people in India who had received Covaxin till then had tested positive while the proportion for Covishield was 0.07%.
Of the close to 24,000 people who got the infection after taking Covaxin, 18,427 tested positive after the first dose and 5,513 after the second dose. With Covishield, 84,198 people tested positive after the first shot while 34,874 were infected after their second shot. The percentages are comparable as substantially higher numbers of Covishield jabs have been given around the country as opposed to Covaxin.
If you have tracked news on vaccines during the pandemic, you’d be familiar with the term “effectiveness" with respect to a vaccine. You’d have also read or heard that no vaccine is 100% effective.
The US diseases watchdog Centres for Disease Control and Prevention (CDC) says that “No vaccine prevents illness 100% of the time and that “for any vaccines, there are breakthrough cases". Even for vaccines that are 90% effective in preventing disease, “a small percentage of people who are fully vaccinated… will still get sick."
Why Do Breakthrough Cases Occur?
Experts say that it normally takes about two weeks for the immune system to build antibodies following vaccination. Now, there can be instances of people who picked up an infection just before, or after, getting their shot. In such cases, the infection would have taken hold even before the full effect of the vaccine could kick in.
Do Newly Emerging Strains Have A Role In Such Breakthrough Cases?
Most vaccines are found to offer some protection against the new variants that have been reported across the world. However, experts are studying the effect of such strains in causing infections in people who have received both doses of a Covid-19 vaccine.
A recent study of 63 mainly healthcare workers at the All India Institute of Medical Sciences (AIIMS) in New Delhi found that the majority of the cases of reinfection involved the new B.1.617.2, or Delta, variant that is now prevalent in India.
“Variants of concern B.1.617.2 and B.1.1.7 responsible for cases surge in April-May 2021 in Delhi, were the predominant lineages among breakthrough infections," said the study.
While the US CDC notes that “some variants might cause illness in some people after they are fully vaccinated", studies in India have found that vaccinated people, even when they test positive, can count on some protection from serious effects.
Why Do Vaccines Remain Necessary?
The AIIMS study found that even though breakthrough cases can crop up, “vaccines may be playing a significant role in reducing mortality". The CDC, in fact, says that “vaccination will protect most people from getting sick".
It adds that “there also is some evidence that vaccination may make illness less severe in people who get vaccinated but still get sick". The CDC stresses that even the worst-case scenarios with breakthrough cases do not take away from the importance of vaccines.
“Some fully vaccinated people will still be hospitalised and die. However, the overall risk of hospitalisation and death among fully vaccinated people will be much lower than among people with similar risk factors who are not vaccinated," the CDC said.
The AIIMS study said that, “of the 63 cases of vaccine breakthrough infections, including 36 who received full doses, there are no reports of mortality even though almost all cases presented with high-grade unremitting fever for 5-7 days".
What You Need To Do
Getting a vaccine if you’re eligible for one is a good idea. But the responsibility to be careful does not end there. Since there is a chance, however minute, of getting Civid-19 after vaccination, experts say that people should continue to wear a mask, maintain social distancing and practice frequent hand-washing/sanitising.