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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 Cold Weather Affects Health: Understanding Winter’s Impact on the Body

Seasonal changes influence human health more than most people realise. Cold weather, in particular, places unique stress on the body and can worsen existing health conditions while increasing susceptibility to new illnesses. Understanding how cold weather affects health is essential for preventing seasonal complications and maintaining wellbeing during winter months.

In India, winter-related health issues vary by region but commonly include respiratory infections, cardiovascular strain and joint discomfort. According to the Indian Council of Medical Research (ICMR) and World Health Organization (WHO), cold exposure is associated with increased morbidity, especially among older adults and people with chronic conditions.

Why Cold Weather Impacts the Body

The human body works constantly to maintain core temperature. In cold environments:

blood vessels constrict to conserve heat
energy expenditure increases
immune responses may weaken
organs work harder to maintain balance

These adaptations, while protective, also create health vulnerabilities.

Increased Risk of Infections

Weakened Immune Response

Cold weather can suppress immune function, making it harder for the body to fight infections.

Factors contributing to winter infections include:

reduced vitamin D due to less sunlight
dry air affecting mucosal defenses
closer indoor contact

Common winter infections include colds, flu and respiratory illnesses.

Respiratory Health Problems

Cold air irritates the respiratory tract.

This can lead to:

worsening asthma symptoms
bronchitis flare-ups
increased cough and breathlessness

WHO reports higher hospital admissions for respiratory illnesses during colder months.

Impact on Heart Health

Cold temperatures affect cardiovascular function.

Blood Vessel Constriction

Cold causes blood vessels to narrow, increasing:

blood pressure
heart workload

This raises the risk of:

heart attacks
strokes

People with existing heart disease are particularly vulnerable.

Joint and Muscle Pain

Cold weather affects musculoskeletal health.

Common complaints include:

joint stiffness
muscle aches
worsening arthritis pain

Lower temperatures reduce joint lubrication and increase sensitivity to pain.

Metabolic and Weight Changes

Winter often leads to:

reduced physical activity
increased calorie intake
metabolic slowdown

These changes contribute to weight gain and worsen metabolic conditions such as diabetes.

Skin and Hydration Issues

Cold air holds less moisture.

This leads to:

dry skin
cracked lips
worsening eczema

Dehydration is also common as thirst perception reduces in cold weather.

Mental Health Effects

Seasonal changes can influence mental wellbeing.

Cold weather is associated with:

low mood
reduced motivation
seasonal affective symptoms

Limited sunlight affects circadian rhythm and serotonin levels.

Cold Weather and Older Adults

Elderly individuals face higher risks due to:

reduced temperature regulation
weaker immunity
existing chronic conditions

Winter-related complications are a significant cause of hospitalisation in older populations.

Why Chronic Diseases Worsen in Winter

Conditions such as:

hypertension
arthritis
asthma
diabetes

often worsen due to reduced activity, stress on organs and infection risk.

Preventive Strategies for Winter Health

Maintain Body Warmth

Layered clothing and warm environments reduce cold stress.

Support Immunity

Adequate nutrition, vitamin intake and sleep strengthen immune defences.

Stay Physically Active

Indoor exercises and regular movement prevent stiffness and metabolic decline.

Manage Chronic Conditions

Regular monitoring and medication adherence are critical during winter.

Hydration and Skin Care

Drinking fluids and using moisturisers prevent dehydration and skin damage.

Role of Preventive Healthcare

Preventive healthcare helps:

identify seasonal risk factors
adjust treatment plans
prevent winter complications

NITI Aayog highlights seasonal preparedness as an important public health strategy.

When to Seek Medical Help

Medical attention is necessary if:

infections persist or worsen
chest pain or breathlessness occurs
joint pain limits mobility
mental health symptoms interfere with daily life

Early care prevents serious outcomes.

Long-Term Impact of Ignoring Winter Health Risks

Ignoring cold weather effects may lead to:

severe infections
cardiovascular events
chronic pain progression
reduced quality of life

Seasonal awareness plays a critical role in long-term health.

Conclusion

Understanding how cold weather affects health allows individuals to take timely preventive measures. Winter increases the risk of infections, heart strain, respiratory problems, joint pain and mental health challenges. With proper warmth, nutrition, activity and preventive healthcare, most cold-related health issues are manageable and preventable. Seasonal care is not optional—it is essential for protecting health and wellbeing throughout the colder months.

References

ICMR – Seasonal Health and Infectious Disease Reports
National Family Health Survey (NFHS-5) – Seasonal Morbidity Data
NITI Aayog – Preventive Healthcare and Seasonal Preparedness Strategy
WHO – Cold Weather and Health Impact Guideline
Lancet – Seasonal Variation in Cardiovascular and Respiratory Diseases
Statista – Winter Health Trends and Illness Data
Indian Journal of Public Health – Climate and Health Studies

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