Call
+918447748545

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 .

Read Blog

Health Problems Linked to Excessive Caffeine Intake: When Too Much Becomes Harmful

Caffeine is one of the most widely consumed stimulants in the world. Found in coffee, tea, energy drinks and many soft drinks, it is often used to improve alertness and combat fatigue. While moderate caffeine consumption can be safe for most people, understanding the health problems linked to excessive caffeine intake is important, especially as daily consumption levels continue to rise in India.

Urban lifestyles, long working hours and increased reliance on energy drinks have made caffeine overconsumption a growing public health concern.

How Caffeine Works in the Body

Caffeine stimulates the central nervous system by blocking adenosine, a chemical responsible for promoting sleep and relaxation.

This results in:

increased alertness
faster heart rate
heightened mental activity

However, overstimulation places stress on multiple body systems.

What Is Considered Excessive Caffeine Intake?

According to WHO and global health guidelines:

up to 400 mg per day is considered safe for most healthy adults

Excessive intake occurs when:

multiple caffeinated beverages are consumed daily
energy drinks are used frequently
caffeine is consumed late in the day

Many people unknowingly exceed safe limits.

Nervous System Overstimulation

Excess caffeine overstimulates the brain.

Common symptoms include:

restlessness
nervousness
tremors
irritability

Chronic overstimulation can worsen stress and reduce emotional stability.

Anxiety and Panic Symptoms

Caffeine increases adrenaline release.

This can:

trigger anxiety attacks
worsen panic disorder
increase feelings of unease

ICMR mental health studies note caffeine as a common trigger for anxiety symptoms in sensitive individuals.

Sleep Disruption and Insomnia

Sleep is one of the first systems affected.

Excessive caffeine:

delays sleep onset
reduces deep sleep
shortens total sleep duration

Even caffeine consumed 6–8 hours before bedtime can impair sleep quality.

Impact on Heart Health

High caffeine intake affects the cardiovascular system.

Possible effects include:

increased heart rate
palpitations
irregular heart rhythm

People with underlying heart conditions are particularly vulnerable.

Blood Pressure Elevation

Caffeine temporarily raises blood pressure.

Chronic excessive intake may:

worsen hypertension
increase cardiovascular risk

NFHS-5 data highlights rising hypertension prevalence in India, making caffeine moderation important.

Digestive System Problems

Caffeine stimulates stomach acid production.

This can cause:

acidity
heartburn
gastritis
bloating

People with sensitive digestion may experience symptoms even at lower doses.

Dependency and Withdrawal Symptoms

Regular high intake leads to caffeine dependence.

Withdrawal symptoms include:

headaches
fatigue
irritability
difficulty concentrating

Dependence reinforces overconsumption cycles.

Effect on Bone Health

Excessive caffeine:

increases calcium loss through urine
may affect bone density over time

This is particularly concerning for older adults and women.

Dehydration and Electrolyte Imbalance

Caffeine has a mild diuretic effect.

High intake without adequate hydration may lead to:

dehydration
muscle cramps
fatigue

Hot climates increase this risk.

Impact on Blood Sugar and Metabolism

Caffeine affects glucose metabolism.

Excessive intake:

worsens insulin sensitivity
increases stress hormone release

This may increase diabetes risk when combined with poor lifestyle habits.

Energy Drinks and Hidden Risks

Energy drinks often contain:

very high caffeine levels
added sugar
stimulants

Lancet reports associate energy drink overuse with heart rhythm disturbances and metabolic stress.

High-Risk Groups

Certain individuals should be especially cautious:

people with anxiety disorders
those with heart disease
pregnant women
individuals with sleep disorders

Safe limits may be lower for these groups.

Signs You May Be Consuming Too Much Caffeine

Warning signs include:

frequent palpitations
chronic insomnia
persistent anxiety
digestive discomfort
reliance on caffeine to function

These signals indicate the need for reduction.

How to Reduce Caffeine Intake Safely

Effective strategies include:

gradual reduction rather than abrupt stopping
switching to decaffeinated options
avoiding caffeine after mid-afternoon
improving sleep and nutrition

Small steps prevent withdrawal symptoms.

Healthier Alternatives for Energy

Better ways to improve energy include:

adequate sleep
balanced meals
hydration
regular physical activity

These support sustained energy without overstimulation.

Role of Preventive Health Awareness

Preventive healthcare focuses on:

identifying lifestyle triggers
reducing dependency habits

NITI Aayog highlights lifestyle modification as key to non-communicable disease prevention.

Long-Term Health Consequences of Ignoring Excess Intake

Chronic caffeine overuse increases risk of:

sleep disorders
anxiety and mood issues
heart rhythm problems
digestive disorders

These conditions often develop gradually.

Conclusion

The health problems linked to excessive caffeine intake extend beyond temporary jitters or sleep loss. Chronic overconsumption strains the nervous system, disrupts sleep, affects heart rhythm, worsens anxiety and impacts digestion and metabolism. While caffeine can be enjoyed safely in moderation, recognising personal limits and maintaining balance is essential for long-term health. Listening to early warning signs and adopting healthier energy habits can prevent serious health consequences.

References

World Health Organization (WHO) – Caffeine Intake and Health Guidelines
Indian Council of Medical Research (ICMR) – Nutrition and Mental Health Studies
National Family Health Survey (NFHS-5) – Hypertension and Lifestyle Risk Data
Lancet – Energy Drinks, Caffeine and Cardiovascular Effects
NITI Aayog – Preventive Health and Lifestyle Modification Reports
Statista – Caffeine Consumption Trends in India

Request A Callback

+91

By using this website/app, I confirm that I am at least 18 years old and consent to the processing of my personal data in accordance with the Terms of Service, Privacy Policy, and Declaration.