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Published on: Jul 17, 2020
2 minute read
By: Dr Rajan Choudhary

MRNA Vaccine Against SARS CoV2

An mRNA Vaccine against SARS CoV2

We have previously discussed vaccines against SARS-CoV-2, the virus responsible for COVID-19. On the 14th of July, a preliminary study was published in the New England Journal of Medicine, an internationally reputable medical journal. This study looks at mRNA vaccines in Phase 1 human clinical trials, a first for the virus. Here we will discuss what this means and the results of the study.

mRNA vaccine

Vaccines target the immune system’s memory by presenting them with pieces of these infective diseases. The small amounts do not cause any infective symptoms, but if the person is infected later in life their body will mount a quicker response and prevent them from falling ill. These vaccines can contain broken up parts of the organisms, “dead” organisms or “live” versions that have been severely weakened so they cannot cause any harm.

In 2018 a new type of vaccine was described. Instead of using pre-made protein markers that identify infectious organisms, mRNA vaccines contain genetic material with instructions to produce these markers. Once injected, the person’s cells use these instructions to produce copies of these protein markers. These markers are displayed on the surface of the cell, which in turn is recognized by the immune system, initiating an immune response and producing protective antibodies.

BENEFITS

A major advantage of RNA vaccines is the ease by which they can be made in a laboratory from a DNA template. During a pandemic, this would result in a rapid response and vaccine against a new disease. Conventional vaccines require the use of chicken eggs or cells to produce the vaccines, which can be expensive and time-consuming. These vaccines can be delivered via injections into the skin, blood, muscle, or organs, needle-free into the skin, or via nasal spray. Because these vaccines are so new, we still do not know the best way to deliver it.

Because these vaccines are not made with parts of infective organisms or from live organisms, they are not infectious and will not cause harm through a strong immune response to the vaccine itself, or by causing the disease they aim to vaccinate against. They also appear to be very efficient at generating a reliable immune response to produce antibodies and are well tolerated with few side effects.

NEEDS IMPROVEMENT

Because these types of vaccines are so new there is still a lot we do not understand about them. They may cause unintended effects that we have not yet encountered in human clinical studies. These vaccines also need to be frozen or refrigerated, and so would not be suitable for countries with limited or no refrigeration facilities.

COVID

The SARS-CoV-2 mRNA vaccine codes for one of the virus’ surface spike proteins, responsible for recognizing target cells and fusing the virus into the cell for entry and infection. It was previously recognized as a target for the SARS and MERS viruses.

45 participants received 2 intramuscular injections 28 days apart. None of the participants had any serious side effects after the first injection, or any side effects significant enough to stop the trial. Many had minor to moderate side effects after their second injection (such as fatigue, chills, headache, myalgia, and pain at the injection site), and half the participants taking high dose vaccines had febrile side effects. Overall the side effects were rated as acceptable.

Prior to the vaccine trials, none of the participants had any antibodies against COVID, or any capacity to stop a COIVD infection. After the injections, all participants had noticeable increases in antibodies produced, measurable in their blood. After 43 days, the participant's blood had enough antibodies to reduce infection by SARS-CoV-2 by over 80%.

What is the takeaway? The vaccine is capable of producing an adequate response to protect the vaccine recipient without eliciting any major side effects. These results will be used in phase 2 clinical trials (enrolment began in May) and a phase 3 trial in July 2020. Essentially this means further human trials to further look for side effects in a larger number of volunteers with a more diverse health profile.

This represents an interesting development in producing a rapid vaccine against a new virus responsible for a world-changing pandemic. This new type of vaccine may be the future of vaccines for a broader range of viruses, bacteria, and even cancers.

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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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