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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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How Inflammation Affects Overall Health: Understanding the Hidden Risks

Inflammation is often misunderstood. While it is a vital protective response of the immune system, persistent or chronic inflammation can quietly damage tissues and increase the risk of serious diseases. Understanding how inflammation affects overall health is crucial in preventing long-term complications and maintaining optimal wellbeing.

According to the World Health Organization and global medical research published in Lancet, chronic inflammation is linked to a wide range of non-communicable diseases, including heart disease, diabetes and autoimmune disorders.

What Is Inflammation?

Inflammation is the body’s natural response to:

infection
injury
toxins
stress

It activates immune cells to eliminate harmful stimuli and promote healing.

There are two main types:

Acute Inflammation

Short-term and protective.
Examples include swelling after injury or fever during infection.

Chronic Inflammation

Long-term, low-grade inflammation that persists even without injury.

Chronic inflammation is harmful.

How Chronic Inflammation Develops

Persistent inflammation can result from:

unhealthy diet
sedentary lifestyle
obesity
chronic stress
environmental toxins
untreated infections

Modern lifestyle patterns contribute significantly to this condition.

Impact on Heart Health

Inflammation damages blood vessels and promotes plaque formation.

This increases risk of:

heart attack
stroke
hypertension

ICMR data highlights cardiovascular disease as a leading cause of death in India, with inflammation playing a contributing role.

Link Between Inflammation and Diabetes

Chronic inflammation interferes with insulin signalling.

This leads to:

insulin resistance
elevated blood sugar
metabolic syndrome

NFHS-5 data shows rising diabetes prevalence, partly linked to inflammatory lifestyle factors.

Effect on Joint and Muscle Health

Inflammatory processes contribute to:

arthritis
joint stiffness
muscle pain

Autoimmune diseases often involve chronic inflammation.

Gut Health and Inflammation

The gut plays a central role in immune regulation.

Poor diet and stress disrupt gut balance, triggering:

inflammatory bowel conditions
digestive discomfort
nutrient malabsorption

Gut inflammation impacts systemic health.

Brain Health and Inflammation

Emerging research suggests chronic inflammation affects:

memory
mood
cognitive performance

Inflammatory markers are associated with depression and neurodegenerative disorders.

Chronic Fatigue and Inflammatory Stress

Persistent inflammation causes:

ongoing fatigue
reduced stamina
sleep disturbances

The immune system remains in constant activation mode.

Role in Autoimmune Disorders

Autoimmune diseases occur when the immune system mistakenly attacks healthy tissues.

Chronic inflammation is central to conditions such as:

rheumatoid arthritis
lupus
inflammatory bowel disease

Signs of Chronic Inflammation

Symptoms may include:

unexplained fatigue
persistent joint pain
digestive issues
frequent infections
skin problems

Early detection is important.

Lifestyle Factors That Increase Inflammation

High Sugar Intake

Excess sugar promotes inflammatory pathways.

Processed Foods

Trans fats and additives trigger immune responses.

Sedentary Lifestyle

Lack of exercise reduces anti-inflammatory benefits.

Poor Sleep

Sleep deprivation increases inflammatory markers.

Chronic Stress

Elevated cortisol disrupts immune balance.

Natural Ways to Reduce Inflammation

Anti-Inflammatory Diet

Include:

leafy greens
fruits rich in antioxidants
nuts and seeds
whole grains

Avoid excessive processed foods.

Regular Physical Activity

Exercise lowers inflammatory markers and improves circulation.

Stress Management

Meditation and breathing exercises reduce stress hormones.

Adequate Sleep

7–8 hours of quality sleep supports immune regulation.

Maintain Healthy Weight

Excess abdominal fat produces inflammatory chemicals.

Role of Preventive Health Screening

Regular tests such as:

blood sugar
lipid profile
inflammatory markers

help monitor risk factors early.

Importance of Early Intervention

Unchecked inflammation increases risk of:

cardiovascular disease
metabolic disorders
organ damage

Timely lifestyle changes reverse early inflammatory effects.

Long-Term Health Benefits of Inflammation Control

Reducing inflammation supports:

heart health
stable blood sugar
improved immunity
enhanced cognitive function
reduced pain

Preventive strategies protect long-term wellbeing.

Conclusion

Understanding how inflammation affects overall health reveals its profound impact on the heart, brain, gut and metabolic systems. While acute inflammation protects the body, chronic inflammation silently contributes to major diseases. Fortunately, lifestyle changes such as balanced nutrition, regular exercise, quality sleep and stress management significantly reduce inflammatory burden. Prevention and early monitoring remain the most effective tools for protecting overall health and ensuring long-term vitality.

References

World Health Organization (WHO) – Chronic Disease and Inflammation Reports
Indian Council of Medical Research (ICMR) – Cardiovascular and Metabolic Health Studies
National Family Health Survey (NFHS-5) – Diabetes and Hypertension Data
NITI Aayog – Preventive Healthcare Strategy Reports
Lancet – Inflammation and Chronic Disease Research

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