It has been now more than a year since the World Health Organization (WHO) declared the Covid-191pandemic. According to Johns Hopkins University dashboard2, the Covid-19 virus has claimed more than 3.1 million lives globally, and laboratory tests have confirmed nearly 150 million cases.
In these past 15 months, the pandemic has caused severe economic and social disruption affecting millions of people worldwide. Many countries have been forced to implement strict lockdowns and harsh restrictions on human activity to curb the spread of this disease, impacting the livelihood of millions of people.
In these bleak times, the COVID-19 vaccination programs that have been rolled out in most countries give us our biggest hope of a return to 'normal' life! We all know that developing 'herd immunity' as quickly as possible is our only chance of achieving normalcy. This 'herd immunity' could be achieved naturally by allowing 60-70% of the population to get infected by Covid19 infections or artificially by vaccinating 60-70% of the population. Both these methods would break the chain of infections, but the former comes at a considerable cost, so there is an urgent need for covid vaccines.
These are the reasons why the ‘herd immunity’ achieved through vaccination would be our best bet:
1. A vaccine has more predictability than the virus3. Vaccination allows a person to build up immunity in a much safer and controlled manner without getting severely ill with COVID-19 and transmitting it to others. Early studies4 showed that assuming a universal 'herd immunity threshold' of 67% and an 'Infection Fatality Ratio' of 0.6%, we would see more than 30 million deaths worldwide. These deaths would be an enormous price to pay to achieve herd immunity naturally. With the worrisome mutants5 found in UK, South Africa, Brazil and India, this figure may even go upwards. Thus, developing natural herd immunity by letting the virus go on a rampage could be cataclysmic, especially for countries with inadequate healthcare infrastructure like India.
2. Vaccination is a controlled program wherein pregnant, lactating, those less than 18 years old, those with allergies and asthma are excluded6. By vaccinating others, we can seek to protect these vulnerable groups through herd immunity. On the other hand, trying to achieve natural 'herd immunity' will put these vulnerable groups at a greater risk.
3. The immunity provided by vaccination can safely be topped up with a yearly booster dose to maintain long-term immunity. On the other hand, natural immunity has been reported by published studies7 lasts 6-7 months, with about 20-30% losing this protection after six months.
4. ICMR has found the risk of breakthrough infections8 (infections occurring after receiving one or two doses of a vaccine) is much lower, at 0.04%. In comparison, reinfection rate9reported by the same agency has been 4.5%, which is 100 times more than the breakthrough infection rate.
5. The severity of disease in breakthrough infections is also much lower, attributed to a much lower viral load10. Reducing the severity of the disease itself has a direct effect on reducing overall mortality. This also leads to a reduced risk of passing on the infection to others.
Despite these advantages, the global COVID-19 vaccination faces several challenges which may impact its success. Reluctance to get vaccinated is one of them. It can be attributed to misinformation being circulated on social media about vaccines. We aim to undo the damage done by this and motivate as many people as possible to go in for vaccines i.e. Covishield and Covaxin in India.