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Published on: Apr 20, 2020
3 minute read
By: Dr Rajan Choudhary

Is Herd Immunity A Valid Strategy For COVID 19?

Yesterday we explained you what Herd Immunity means and how it works, today we will take the discussion further to determine whether it is effective and can be recommended in the current context.

COVID-19 currently does not have a cure or a vaccine. Lockdown is the only strategy that appears to be working. Could implementing policies that encourages herd immunity be used to accelerate immunity in the population without the need for a vaccine?

INFECTIVITY

For the strategy to work we need to know a few things about the virus. How infective is it? In one of our earliest blogs we discussed infectivity at length and determined that the R0 (infectivity) may be between 2 and 3. This means each person with the virus can infect around 2-3 people at a time. Whilst this is not as high as Mumps (10-12) it is much higher than the common flu. The higher the R0 the more people that need to be immunised before herd immunity is achieved. For COVID it is estimated that 70% of the population need to be infected.

This is based off our current testing. Due to shortages in testing kits, only testing those that have a high likelihood of being infected and poorly organised testing infrastructure in some countries, we are likely underestimating. The number of people infected may be much higher as we are missing those that are asymptomatic but still have the disease and are still passing the disease on.

MORTALITY

Secondly, we need to know the mortality from COVID-19. Early estimates of mortality were as high as 10%, as we had little data on how many people were truly infected, but as the number of infected cases rose, and testing amongst the infected and symptomatic population rose, a more accurate mortality has been found to be around 1%. There is a risk we may still be underestimating the true mortality, as some cities have noted a spike in cardiac deaths, and some evidence supports possible cardiac damage due to COVID. But from the data we have, we know its mortality is lower than MERS (34%) and SARS (10%) but more than influenza (0.1%).

estimates of the COVID-19 case fatality rate

Whilst we have some data on who is likely to suffer from severe COVID symptoms (elderly, immunocompromised, people with heart or lung problems) we still cannot accurately determine who will get severe COVID in the “low risk” population. Simply because someone is young and healthy does not mean they will not die from COVID.

LENGTH OF IMMUNITY

Third we need to know how long this immunity will last. Similar coronaviruses responsible for the common cold usually create immunity that lasts for a few months, which is why we often get the cold repeatedly. A virus is also very prone to mutations that can change the structure and functions of its proteins, proteins responsible for tagging, latching on to and entering cells. If the structure of these proteins changes enough, then our antibodies will not be able to bind on, and new types of antibodies will have to be made with a slightly different structure. This effectively means our bodies have to start from step 1 again to create immunity, and we have to make new vaccines. This mutation rate is why we have to make new vaccines every season for the flu.

LONG TERM COMPLICATIONS

Finally, we need to know if there are any long-term implications from a viral infection. Again, this is something we do not know yet, as the virus has only been around for a few months. There may be implications for the cardiovascular system, long term breathing problems or more. And even if the complication rate appears relatively low (say, 1%), if millions of people are allowed to get infected, by definitions thousands or tens of thousands of people will have these complications, complications that can lead to issues later in life or an early death.

CONCLUSION

So, is herd immunity a viable strategy for COVID? Without a safe vaccine the general consensus appears to be no.

We don’t know how infective the virus really is or how many people it has infected

A 1% death rate is still very high. This means for every 100 people to be infected; one will die. This would mean hundreds of thousands of people dead in a country with a population over 10 million. It is unacceptably high.

If the death rate is 1%, then hospitalisation rate is likely higher. Almost all countries do not have capacity to have 1% of the population in hospital. Overwhelming the healthcare system will lead to poorer care, and worse care for those who do not have COVID. Leading to more people coming to serious harm or dying as a result of poor healthcare, not because of COVID.

We don’t know the long-term effects of COVID. By purposefully infecting people instead of waiting for a vaccine we may be causing unnecessary damage to a person’s health that only becomes apparent later in life. But this is speculation as we do not currently know if COVID has long term effects,

We don’t know if all of the risks above will amount to anything. The immunity may not last long enough, leading to another spike in infections and mortality.

Mass vaccination appears to be the safest strategy. And though human clinical trials have started on a number of vaccines, we are still months away from deployment. Until then we should not come out of lockdown prematurely, not until we have received an unbiased assessment from public health officials that states it is safe.

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Role of Nutrition in Disease Prevention: How Food Choices Shape Long-Term Health

Disease prevention is no longer limited to vaccinations and medical screenings. Modern healthcare increasingly recognises nutrition as one of the most powerful tools for preventing illness before it begins. The role of nutrition in disease prevention is especially important in India, where lifestyle-related diseases account for a large share of premature illness and mortality.

According to the Indian Council of Medical Research (ICMR) and the National Family Health Survey (NFHS-5), poor dietary patterns contribute significantly to rising cases of diabetes, heart disease, obesity and hypertension. Unlike genetic factors, nutrition is a modifiable risk factor, meaning everyday food choices can actively protect health.

Why Nutrition Is Central to Disease Prevention

1. Nutrition regulates metabolic health

Balanced diets help maintain:

healthy blood sugar levels
optimal cholesterol balance
stable blood pressure

Disruption in these systems increases disease risk.

2. Nutrition strengthens immunity

WHO highlights that immune function depends heavily on adequate intake of vitamins, minerals and protein.

3. Nutrition controls inflammation

Chronic low-grade inflammation is linked to most lifestyle diseases. Diets rich in whole foods reduce inflammatory markers.

Major Diseases Influenced by Nutrition

Diabetes and Prediabetes

Excess refined carbohydrates and sugar drive insulin resistance.

Preventive nutrition focuses on:

whole grains
fibre-rich vegetables
adequate protein
controlled portion sizes

ICMR data shows that dietary modification can delay or prevent type 2 diabetes in high-risk individuals.

Cardiovascular Disease

Heart disease remains a leading cause of death in India.

Nutrition impacts:

cholesterol levels
blood pressure
arterial inflammation

Diets low in trans fats and high in fibre significantly reduce cardiovascular risk, as confirmed by WHO and Lancet studies.

Obesity

Obesity increases the risk of multiple chronic diseases.

Preventive nutrition addresses:

calorie density
food quality
satiety regulation

NFHS-5 reports a steady rise in overweight and obesity across age groups.

Hypertension

High sodium intake and low potassium intake contribute to high blood pressure.

Preventive dietary strategies include:

reducing processed foods
increasing fruits and vegetables
maintaining mineral balance

Certain Cancers

Diet influences cancer risk through:

antioxidant intake
fibre consumption
reduced exposure to carcinogenic compounds

WHO estimates that a significant percentage of cancers are preventable through diet and lifestyle changes.

Key Nutrients That Support Disease Prevention

Fibre

Supports gut health, blood sugar control and cholesterol reduction.

Protein

Essential for muscle health, immune function and metabolic balance.

Healthy Fats

Omega-3 fats reduce inflammation and protect heart health.

Micronutrients

Iron, zinc, vitamin D and B vitamins are essential for metabolic and immune regulation.

NFHS-5 highlights widespread micronutrient deficiencies in India, increasing disease vulnerability.

Role of Gut Health in Prevention

The gut microbiome plays a major role in:

immune regulation
inflammation control
nutrient absorption

Fermented foods and fibre-rich diets support healthy gut bacteria, strengthening disease resistance.

Why Preventive Nutrition Works Best Early

Nutrition is most effective when applied:

before disease onset
during pre-disease stages
alongside regular health screening

Once disease progresses, nutrition remains supportive but may not reverse damage fully.

Nutrition vs Medication in Prevention

Medication treats disease; nutrition reduces risk.

WHO and NITI Aayog emphasize that:

preventive nutrition reduces disease incidence
lifestyle modification lowers healthcare burden
early nutrition changes reduce dependency on long-term medication

Both approaches work best when combined appropriately.

Workplace and Community Role in Preventive Nutrition

Structured nutrition programs at workplaces and communities:

improve awareness
support behaviour change
reduce population-level disease burden

Lancet studies show that group-based nutrition interventions improve long-term adherence.

Common Myths About Nutrition and Disease Prevention

Myth 1: Supplements replace healthy food

Whole foods provide better long-term protection.

Myth 2: Prevention requires extreme diets

Consistency matters more than restriction.

Myth 3: Nutrition only matters after diagnosis

Early nutrition is most effective before disease develops.

Building a Preventive Nutrition Routine

Effective preventive nutrition includes:

regular meals
diverse food groups
portion awareness
minimal processed foods
hydration

Small daily choices compound into long-term health benefits.

Long-Term Impact of Preventive Nutrition

Consistent healthy eating leads to:

reduced disease risk
improved energy and productivity
better immune resilience
lower healthcare costs
improved quality of life

NITI Aayog identifies nutrition as a cornerstone of sustainable healthcare systems.

Conclusion

Understanding the role of nutrition in disease prevention empowers individuals to take control of their health long before illness develops. Balanced, consistent nutrition reduces inflammation, supports immunity and protects against chronic diseases that burden India’s healthcare system. Preventive nutrition is not about short-term fixes but about building lifelong habits that support health, resilience and longevity.

References

ICMR – Nutrition and Lifestyle Disease Prevention Reports
National Family Health Survey (NFHS-5) – Dietary and Metabolic Health Data
NITI Aayog – Preventive Healthcare and Nutrition Strategy Reports
WHO – Diet, Nutrition and Chronic Disease Prevention Guidelines
Lancet – Nutrition and Disease Risk Reduction Studies
Statista – Dietary Trends and Health Outcomes India
EY-FICCI – Preventive Healthcare and Nutrition Economics

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