Building herd immunity may not work in tackling the COVID-19 outbreak since there isn’t yet a vaccine for SARS-CoV-2, according to Giridhar R Babu, professor and head of life course epidemiology, Public Health Foundation of India.
Herd immunity refers to vaccinating a bulk of the population to prevent them from getting infected and therefore, from transmitting the germ responsible for the infection to other people. This way, even those who cannot be vaccinated are protected.
Babu has worked with the World Health Organization for nearly six years, during which his efforts included stopping polio transmission in Karnataka and initiation of measles surveillance. He has also worked as a research associate for Multi Centre AIDS Cohort (MACS).
"Vaccinations are the safest way to practice herd immunity in a population," Babu told Moneycontrol in an interview.
Frequently Asked Questions
A vaccine works by mimicking a natural infection. A vaccine not only induces immune response to protect people from any future COVID-19 infection, but also helps quickly build herd immunity to put an end to the pandemic. Herd immunity occurs when a sufficient percentage of a population becomes immune to a disease, making the spread of disease from person to person unlikely. The good news is that SARS-CoV-2 virus has been fairly stable, which increases the viability of a vaccine.
There are broadly four types of vaccine — one, a vaccine based on the whole virus (this could be either inactivated, or an attenuated [weakened] virus vaccine); two, a non-replicating viral vector vaccine that uses a benign virus as vector that carries the antigen of SARS-CoV; three, nucleic-acid vaccines that have genetic material like DNA and RNA of antigens like spike protein given to a person, helping human cells decode genetic material and produce the vaccine; and four, protein subunit vaccine wherein the recombinant proteins of SARS-COV-2 along with an adjuvant (booster) is given as a vaccine.
Vaccine development is a long, complex process. Unlike drugs that are given to people with a diseased, vaccines are given to healthy people and also vulnerable sections such as children, pregnant women and the elderly. So rigorous tests are compulsory. History says that the fastest time it took to develop a vaccine is five years, but it usually takes double or sometimes triple that time.
Q. There's already a lot of discussion on a 'staggered exit' plan; some states are looking to extend the lockdown beyond April 14. What should be India's second phase?
A. Based on the number of cases in each district, we need to do the district-wise micro-planning and phasing of the COVID-19 response.
Q. There's a lot of debate on why is India not testing enough. How South Korea went about the crisis. What is the correct way to deal with this public health crisis?
A. We should not and cannot do like South Korea; there is no purpose in doing indiscriminate testing. However, we need to expand, and India is gradually expanding its testing capacity. India has conducted 47 tests per million population as of April 5. Kerala, which has the highest testing rate of 276 tests per million people, has one of the least case fatalities at 0. 65 percent. But Madhya Pradesh, Bihar, Punjab, West Bengal, and Gujarat have a higher case fatality average (of about 3 percent to 9 percent) compared to the national average of 2.3 percent.
Testing is also low in these states, with about just 15 tests or less per million people. So the next stage is at the state and district level. Containment measures with detection of cases based on the syndromic approach and testing (as and when available) should be the mainstay of the next course in the response.
Q. You have had a body of work in dealing with something like polio, measles, that used herd immunity. What's your take on developing herd immunity in the case of COVID-19?
A. We simply do not know enough about COVID-19. Whether infection once provides life long immunity or does it affect again etc. Until we have a vaccine, physical distancing, using masks, hygiene practices (frequent handwashing) and use of personal protective equipment’s (PPEs) are the only ways to prevent from contracting and potentially spreading COVID-19.
The reasons why herd immunity isn’t the answer to stopping the spread of the new coronavirus are quite a few. There isn’t yet a vaccine for SARS-CoV-2. Vaccinations are the safest way to practice herd immunity in a population.
Scientists don’t know if you can contract SARS-CoV-2 and develop COVID-19 more than once.
Vulnerable members of society, such as older adults and people with some chronic health conditions, could get very sick if they’re exposed to this virus. Hospitals and healthcare systems may be overburdened if many people develop COVID-19 at the same time.
Q. Do you think the national lockdown helped in flattening the curve?
A. Yes, India was right on time to implement lockdown early enough to prevent mass casualties, and we have a lower number of cases detected (even after taking into account testing rates). We have definitely extended the flattening, as containment measures determine it now.
Q. You've had a body of work in public health. What is your assessment of the state of our health infrastructure? For a country as vast as India, our allocation on public health is less than 1.5 percent of the country's GDP.
A. Despite the implementation of the National Health Mission over a period of nine years since 2005, the public health system in the country continues to face formidable challenges. The main challenges confronting the public hospitals today are lack of dedicated public health cadre, deficient infrastructure, unmanageable patient load, quality of services, and high out of the pocket expenditure.
As a result, if one is not already in that state, medical expenditure might make one poor. Low priority accorded to health has led to limited investments in both health infrastructure and health data.
It is time to strengthen the National Centre for Disease Control, and its Integrated Disease Surveillance Programme (ISDP) with greater funding equivalent to CDC (Centers for Disease Control and Prevention) Atlanta and higher investments in preventive public health interventions.
Q. Europe and the USA seem to be struggling to tackle the pandemic. Given that population isn't as big a concern as India, what's going wrong there?A. The Asian countries, namely China, South Korea, Singapore, and Taiwan, are doing reasonably well in containing pandemic. Unfortunately, Europe and the USA are struggling to tackle the pandemic. India had a considerable share of learning from these countries and has taken urgent and significant actions despite the high population and our limitations in health care services.