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Published on: Nov 13, 2020
2 minute read
By: Dr Rajan ( Medical Second Opinion Cell)

What Are Some Common Side Effects Of The COVID-19 Vaccine?

COVID Vaccine, the Pfizer update

On Monday Pfizer announced to the world the vaccine, once it has been developing with Germany's BioNTech, was found to be more than 90?fective. If this is substantiated, it may be possible for countries to receive the vaccine before the end of the year.

The Vaccine is an mRNA Vaccine, a novel method that introduces viral RNA into the body via a viral coat. The vaccine is incorporated into the person's cell, where the viral RNA is read and viral proteins are produced, including the coronavirus coat proteins. As the body reads and recognizes these proteins, it produces antibodies against these viral proteins and activates immune T cells against the virus.

The Pfizer results are based of a phase 3 clinical trial with 43, 538 participants with a diverse background. In this trial, the participants were split between those receiving a vaccine, and those who received a placebo with no effect. The vaccine is administered in two parts, with a 90?ficacy obtained 7 days after the second dose. This would mean a person is vaccinated just 28 days after the initial vaccination.

The FDA usually looks for a minimum 50?ficacy in vaccination when approving new vaccines. It may surprise you that the annual flu jab is also estimated to be 50?fective. The data from Pfizer was verified by an external, independent Data Monitoring Committee. It used data from 94 patients enrolled in the trial and subsequently developed COVID. It is from this groupset that 90% of efficacy is obtained. This is not the final data analysis, and further publications are expected in late November, with a potential FDA Emergency Use Authorisation approval if the data continues to show promise.

If approved, Pfizer has the ability to make 50 million shots before the end of the year, and 1.3 billion by the end of 2021. Many countries are clamoring for their fair share of these limited resources; the US has already negotiated 200m shots, UK 50m, and Germany (one of the major financers for the Pfizer vaccine) over 300m for European Countries.

We should emphasize that rapid vaccine development on this scale at this speed was unheard of prior to COVID. Usually, the animal studies for vaccines can take 1-2 years. In that time Pfizer and others have managed phase 1-3 clinical trials in humans, something that usually takes upwards of 10 years.

There are many unanswered questions that remain from this information.

How safe is the vaccine? Whilst safety information was not published, overall the vaccine appears to have minimal side effects. This is particularly difficult to state however since mRNA vaccines have never been used in people before.
Does the vaccine prevent transmission? In theory, yes. If you are immunized the replication of the virus should be limited significantly, so the number of viruses in each cough will be much lower. However, we do not have data to prove that there is no transmission, but that is also because we have very little data overall.
How long does the protection last? This is a very critical question. The 90?fectiveness rate was calculated just 7 days after the second shot, but it is likely this will change as data is collected over the long term. Some studies have suggested the antibody response fades within months following COVID infection. T Cell immunity on the other hand can stay for years, and it may be the effectiveness of creating a T cell immunity that dictates just how good this vaccine will be .

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How Lack of Sleep Weakens Immunity: Why Poor Sleep Makes You Fall Sick More Often

Sleep is one of the most powerful yet overlooked pillars of health. While nutrition and exercise receive significant attention, sleep often takes a back seat in modern lifestyles. Understanding how lack of sleep weakens immunity reveals why people who sleep poorly fall sick more often, take longer to recover and experience chronic inflammation.

In India, late-night work culture, excessive screen time and irregular schedules have made sleep deprivation increasingly common across age groups.

The Link Between Sleep and the Immune System

The immune system relies on sleep for:

repair and regeneration
immune cell production
inflammation control

During deep sleep, the body releases cytokines and antibodies that protect against infections.

What Happens to Immunity During Sleep

While sleeping:

immune cells identify pathogens
inflammatory responses are regulated
memory T-cells strengthen immune memory

This nightly process prepares the body to fight infections effectively.

How Sleep Deprivation Disrupts Immune Function

When sleep is inadequate:

immune cell activity decreases
antibody production drops
inflammation increases

WHO studies confirm that sleep deprivation weakens immune defence mechanisms.

Increased Risk of Infections

People who sleep less than 6 hours regularly:

fall sick more often
catch colds and flu easily
recover slower from illness

Lancet research shows a strong link between sleep duration and infection susceptibility.

Impact on Inflammation

Poor sleep increases inflammatory markers.

Chronic inflammation:

weakens immune response
increases risk of chronic diseases

ICMR reports highlight sleep deprivation as a contributor to low-grade systemic inflammation.

Effect on Vaccine Response

Sleep quality affects how well vaccines work.

Studies show:

poor sleep reduces antibody response
adequate sleep improves vaccine effectiveness

Sleep is essential for immune memory formation.

Hormonal Changes That Affect Immunity

Sleep regulates hormones such as:

cortisol
melatonin

Lack of sleep increases cortisol, which suppresses immune function.

Stress, Sleep and Immunity

Sleep deprivation and stress reinforce each other.

High stress:

disrupts sleep
suppresses immune cells

This cycle weakens overall resistance to illness.

Impact on Gut Immunity

The gut hosts a major part of the immune system.

Poor sleep:

disrupts gut microbiome
weakens gut immunity

Lancet studies link sleep deprivation to gut-related immune dysfunction.

Why Children and Older Adults Are More Vulnerable

Sleep deprivation affects:

children’s developing immune systems
older adults’ already weakened immunity

Adequate sleep is especially important in these age groups.

Signs Your Immunity Is Affected by Poor Sleep

Warning signs include:

frequent infections
slow wound healing
constant fatigue
increased allergies

These symptoms indicate compromised immune defence.

Long-Term Health Risks of Poor Sleep

Chronic sleep deprivation increases risk of:

infections
autoimmune disorders
metabolic diseases
heart disease

Sleep loss affects nearly every body system.

Role of Preventive Health Awareness

Preventive healthcare emphasises:

sleep as a foundation of immunity
early lifestyle correction

NITI Aayog recognises sleep hygiene as essential for population health.

How to Improve Sleep for Better Immunity

Effective strategies include:

fixed sleep and wake times
limiting screen exposure before bed
avoiding caffeine late in the day
creating a dark, quiet sleep environment

Consistency matters more than duration alone.

Myths About Sleep and Immunity

Myth: You can catch up on sleep later
Fact: Chronic sleep debt harms immunity.

Myth: Sleeping pills improve immunity
Fact: Natural sleep is more beneficial.

Why Sleep Is a Preventive Medicine

Sleep:

costs nothing
requires no equipment
delivers powerful immune protection

It is one of the most effective preventive health tools.

Conclusion

Understanding how lack of sleep weakens immunity highlights the critical role of sleep in protecting the body from infections and chronic disease. Poor sleep disrupts immune cell function, increases inflammation and reduces resistance to illness. Prioritising consistent, quality sleep is not optional—it is essential for strong immunity, faster recovery and long-term health. Protecting sleep today strengthens immune defence for tomorrow.

References

Indian Council of Medical Research (ICMR) – Sleep, Immunity and Inflammation Studies
World Health Organization (WHO) – Sleep and Immune Health Guidelines
National Institutes of Health – Sleep Deprivation and Immunity
Lancet – Sleep Duration and Infection Risk
NITI Aayog – Preventive Health and Lifestyle Recommendations

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