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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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Chest Pain While Breathing: Causes, Warning Signs, and When to Seek Urgent Care

Chest pain is one of the most alarming symptoms a person can experience, especially when it worsens during breathing. Chest pain while breathing, also known as pleuritic chest pain, often indicates involvement of the lungs, chest wall or surrounding structures. While some causes are mild, others can be life-threatening and require immediate medical attention.

In India, respiratory infections, air pollution, sedentary lifestyles and delayed medical care contribute significantly to chest-related symptoms.

What Does Chest Pain While Breathing Mean?

Chest pain while breathing refers to pain that:

worsens with deep inhalation or exhalation
may feel sharp, stabbing or burning
can be localized or spread across the chest

Pain intensity often increases with coughing or movement.

Common Causes of Chest Pain While Breathing

Lung Infections (Pneumonia)

Pneumonia inflames lung tissue and surrounding membranes.

Symptoms include:

chest pain while breathing
fever
cough
breathlessness

ICMR data identifies pneumonia as a major cause of respiratory illness in India.

Pleuritis (Inflammation of Lung Lining)

The pleura are thin membranes surrounding the lungs.

When inflamed:

breathing causes friction
sharp chest pain occurs

Pleuritis often follows viral infections or pneumonia.

Pulmonary Embolism

A blood clot in the lungs causes:

sudden chest pain
rapid breathing
severe breathlessness

This is a medical emergency requiring immediate care.

Chest Wall Muscle Strain

Muscle strain due to:

heavy lifting
intense coughing
poor posture

can cause pain during breathing or movement.

Costochondritis

Inflammation of rib cartilage causes:

localized chest pain
pain worsened by breathing or pressing on the chest

This condition is painful but not life-threatening.

Pneumothorax (Collapsed Lung)

Air leakage into the chest cavity causes:

sudden sharp chest pain
breathlessness

Often seen after trauma or in individuals with lung disease.

Heart-Related Causes

Though heart pain usually does not worsen with breathing, conditions such as:

pericarditis (heart lining inflammation)

can cause chest pain that changes with respiration.

Acid Reflux and Esophageal Spasm

Gastrointestinal causes may mimic chest pain.

However:

pain usually relates to meals
breathing-related pain should be evaluated carefully

Anxiety and Panic Disorders

Anxiety can cause:

chest tightness
rapid breathing
discomfort while breathing

Medical causes must be ruled out before attributing pain to anxiety.

Warning Signs That Require Emergency Attention

Seek immediate medical care if chest pain while breathing is associated with:

sudden onset
severe breathlessness
bluish lips or fingers
dizziness or fainting
sweating
coughing up blood

These may indicate life-threatening conditions.

Risk Factors for Serious Chest Pain

Higher risk occurs in people with:

smoking history
recent surgery or long travel
lung disease
heart disease
clotting disorders

Early evaluation is critical.

Diagnostic Evaluation

Doctors may recommend:

physical examination
chest X-ray
ECG
blood tests
CT scan

Timely diagnosis saves lives.

Why Chest Pain Should Not Be Ignored

Ignoring chest pain can lead to:

delayed treatment
worsening respiratory failure
preventable complications

WHO emphasises early symptom recognition for better outcomes.

Impact of Air Pollution and Lifestyle

Air pollution increases:

lung inflammation
infection risk

Sedentary habits reduce lung capacity, worsening symptoms.

Preventive Measures

Helpful preventive steps include:

avoiding smoking
staying physically active
managing respiratory infections early
maintaining good posture
staying hydrated

Preventive care reduces risk.

Role of Preventive Health Checkups

Regular health screening helps detect:

early lung disease
heart risk factors
chronic inflammation

Early intervention prevents emergencies.

When Chest Pain Is Less Likely Serious

Pain may be less concerning if:

localized
reproducible on touch
improves with rest

However, medical confirmation is still necessary.

Importance of Timely Medical Consultation

Chest pain should always be evaluated by a healthcare professional.

Delaying care can:

increase complications
raise mortality risk

Early action saves lives.

Conclusion

Chest pain while breathing is a critical symptom that should never be ignored. While causes range from muscle strain and infections to serious lung and heart conditions, only proper medical evaluation can determine the exact cause. Early diagnosis, timely treatment and preventive care are essential to protect respiratory and cardiovascular health. When it comes to chest pain, it is always safer to act early than to wait.

References

Indian Council of Medical Research (ICMR) – Respiratory and Cardiovascular Health Reports
World Health Organization (WHO) – Chest Pain and Respiratory Symptoms Guidelines
National Family Health Survey (NFHS-5) – Adult Respiratory Health Data
Lancet – Pulmonary Embolism and Chest Pain Research
NITI Aayog – Preventive Healthcare and Early Symptom Recognition

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