A raging debate is going on whether the salvation from COVID-19 can be attained through herd immunity. With no vaccine in sight, many are advocating it. But what is it? Will it be effective? Has the union govt advocated the same? What about Kerala which not only has high population density but also a high concentration of the elderly and people with comorbidity? TNIE examines.
1. WHAT IS HERD IMMUNITY?
Herd immunity or community immunity occurs when a large percentage of the community gets immune to a disease. It can be achieved either through vaccination or through natural infection. With no vaccine shots available, it means allowing the virus to run through the population.
2 WHAT WILL HAPPEN THEN?
Once a large section of a community, the herd that is, becomes immune, it will make the spread of disease from person to person unlikely.
3. HOW WILL IT HAPPEN?
Only a percentage of the population will get the disease and spread it. Epidemiologists call it threshold proportion. However, when the proportion of the population that is immune to the disease becomes higher than this percentage, the spread of the disease will decline. This proportion is called herd immunity threshold.
4. HAS IT BEEN EFFECTIVE?
The preferred mode of herd immunity is through vaccine as it creates immunity without causing illness or resulting complications. However, it involves risks like people’s opposition to vaccines, revaccination and others. Though herd immunity can be achieved through natural infection, it will come at the cost of many lives.
5. WHAT ABOUT COVID-19?
Search for a Covid vaccine is on. Hence, attaining herd immunity through vaccine can be ruled out for now. As for natural infection, it is unknown if contracting Covid-19 makes one immune to future infection. Also, though getting infected creates long-lasting immunity, several people would have to get infected to reach the herd immunity threshold.
6. WHAT IS THE WHO’S TAKE?
WHO’s chief scientist Dr Soumya Swaminathan has said it needs at least 60 to 70% of the population to have immunity to really break the chain of transmission. If it is allowed to happen naturally, it will take a long time but more importantly, it’s going lead to a lot of collateral damage. Thus, it’s not a good idea to try to achieve herd immunity by letting the infection run wild in the population.
7. WHAT IS THE CENTRE'S STANCE?
As per a statement made by Union Minister of State for Health Ashwini Kumar Choubey in the Rajya Sabha on Sunday, trying to achieve herd immunity without established pharmaceutical interventions may have disastrous consequences in terms of morbidity and mortality.
8. HAS ANY OTHER COUNTRY EXPERIMENTED WITH IT?
While many countries, including the UK and the US, are said to be pondering a policy of herd immunity, they have denied the same publicly. However, Sweden experimented with it and is said to be dealing with disastrous consequences like more hospitalisations and deaths.
9. WILL IT BE FEASIBLE FOR KERALA?
Kerala cannot adopt such a strategy. For a state with large population density and high concentration of elderly and people with comorbidities, trying this will prove disastrous. Health Minister K K Shailaja has already ruled out such an experiment.
Inputs by: DILEEP V KUMAR