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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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Shortness of Breath Causes: From Common Triggers to Serious Health Conditions

Shortness of breath, medically known as dyspnea, is a symptom that ranges from mild discomfort during exertion to a distressing sensation of not getting enough air. In India, increasing air pollution, lifestyle diseases and respiratory infections have made breathlessness a frequent complaint across age groups. Understanding shortness of breath causes is essential to identify when it is harmless and when it signals a medical emergency.

What Is Shortness of Breath?

Shortness of breath refers to difficulty breathing or a feeling of air hunger.

It may present as:

rapid breathing
shallow breathing
tightness in the chest
inability to take a deep breath

The sensation can develop suddenly or gradually.

Common and Benign Causes of Shortness of Breath

Physical Exertion

During exercise, the body demands more oxygen.

Temporary breathlessness during:

climbing stairs
running
heavy physical work

is normal and resolves with rest.

Anxiety and Panic Attacks

Stress and anxiety alter breathing patterns.

Symptoms include:

rapid breathing
chest tightness
dizziness

These episodes often resolve with calming techniques.

Respiratory Causes of Shortness of Breath

Asthma

Asthma causes airway narrowing and inflammation.

Symptoms include:

wheezing
chest tightness
breathlessness during exertion or at night

Asthma is a leading cause of chronic breathlessness.

Chronic Obstructive Pulmonary Disease

COPD includes chronic bronchitis and emphysema.

Risk factors include:

smoking
indoor air pollution
occupational exposure

WHO identifies COPD as a major cause of breathlessness in adults.

Respiratory Infections

Infections such as pneumonia and bronchitis reduce lung capacity.

Breathlessness may be accompanied by:

cough
fever
chest pain

Severe infections require urgent treatment.

Heart-Related Causes of Shortness of Breath

Heart Failure

The heart fails to pump blood efficiently.

This leads to:

fluid accumulation in lungs
breathlessness on exertion
breathlessness while lying flat

ICMR data shows heart disease as a major contributor to unexplained breathlessness.

Coronary Artery Disease

Reduced blood supply to the heart can cause:

breathlessness
chest discomfort
fatigue

This may occur even without chest pain in some individuals.

Blood and Metabolic Causes

Anemia

Low hemoglobin reduces oxygen delivery.

Common symptoms include:

fatigue
breathlessness on mild activity
pale skin

NFHS-5 highlights anemia as highly prevalent in India.

Thyroid Disorders

Hyperthyroidism increases metabolic demand, causing breathlessness.

Hypothyroidism may contribute indirectly through weight gain and reduced stamina.

Lung Circulation Disorders

Pulmonary Embolism

A blood clot in the lungs causes sudden, severe breathlessness.

This is a medical emergency and may be accompanied by:

chest pain
coughing blood
fainting

Immediate treatment is critical.

Lifestyle-Related Causes

Obesity

Excess body weight restricts lung expansion.

Breathlessness occurs due to:

increased oxygen demand
reduced lung volumes

Weight management improves breathing efficiency.

Sedentary Lifestyle

Poor physical conditioning reduces respiratory muscle strength.

Even mild exertion may cause breathlessness.

Environmental and Occupational Factors

Air Pollution

Pollutants irritate airways and reduce lung function.

Urban populations experience higher rates of breathlessness.

Workplace Exposure

Dust, chemicals and fumes increase respiratory risk.

Protective measures are essential in high-risk occupations.

When Shortness of Breath Is a Warning Sign

Seek urgent care if breathlessness:

starts suddenly
worsens rapidly
occurs at rest
is associated with chest pain, bluish lips or confusion

These may indicate life-threatening conditions.

How Shortness of Breath Is Diagnosed

Evaluation may include:

physical examination
chest imaging
blood tests
lung function tests
heart evaluation

Diagnosis focuses on identifying the root cause.

Preventive Measures and Lifestyle Care

Prevention includes:

regular physical activity
pollution protection
smoking cessation
weight control
managing chronic conditions

Preventive healthcare reduces long-term risk.

Importance of Early Medical Evaluation

Delayed diagnosis can worsen outcomes, especially in:

heart disease
lung infections
anemia

Early care improves treatment success.

Conclusion

Shortness of breath causes range from temporary exertion and anxiety to serious heart, lung and blood disorders. While occasional breathlessness may be harmless, persistent or sudden symptoms should never be ignored. Understanding the underlying causes and seeking timely medical evaluation can prevent complications and save lives. Paying attention to changes in breathing is an essential step toward protecting overall health and wellbeing.

References

Indian Council of Medical Research (ICMR) – Respiratory and Cardiac Health Reports
World Health Organization (WHO) – Breathlessness and Chronic Disease Guidelines
National Family Health Survey (NFHS-5) – Anemia and Respiratory Health Data
Lancet – Dyspnea Evaluation and Outcomes Research
NITI Aayog – Non-Communicable Disease Prevention Reports
Statista – Respiratory Disease and Air Pollution Trends

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