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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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Asthma Symptoms in Adults: Early Signs, Triggers, and When to Seek Care

Asthma is often perceived as a childhood condition, but a significant number of cases develop or persist into adulthood. In India, adult asthma is increasingly recognised due to rising air pollution, occupational exposure and lifestyle-related risk factors. Unfortunately, asthma symptoms in adults are frequently misdiagnosed as recurrent infections, allergies or age-related breathlessness, leading to delayed treatment.

Understanding adult asthma symptoms is critical for early diagnosis, effective control and prevention of severe attacks.

What Is Asthma?

Asthma is a chronic inflammatory disease of the airways. In asthma, the airways become:

inflamed
narrow
overly sensitive to triggers

This leads to difficulty in breathing, especially during exposure to specific stimuli.

Why Adult Asthma Is Often Missed

Adult asthma symptoms may:

appear gradually
vary in severity
mimic common respiratory conditions

According to Indian Council of Medical Research and WHO data, many adults remain undiagnosed for years, increasing the risk of complications.

Common Asthma Symptoms in Adults

Wheezing

A high-pitched whistling sound while breathing, especially during exhalation, is a classic asthma sign.

Shortness of Breath

Adults with asthma often feel:

breathless during routine activities
difficulty taking deep breaths

This may worsen at night or early morning.

Chest Tightness

Many describe a sensation of pressure or tightness in the chest, which can be mistaken for heart-related issues.

Chronic Cough

A persistent cough, especially:

at night
early morning
after exercise

is a common but overlooked asthma symptom.

Symptoms That Worsen With Triggers

Asthma symptoms often intensify after exposure to specific triggers.

Air Pollution and Smoke

Urban pollution, vehicle emissions and indoor smoke significantly worsen asthma symptoms in adults.

Allergens

Dust mites, pollen, mould and pet dander are common triggers.

Respiratory Infections

Viral infections can trigger asthma flare-ups or reveal undiagnosed asthma.

Physical Activity

Exercise-induced asthma causes breathlessness and wheezing during or after physical exertion.

Weather Changes

Cold air, humidity and sudden temperature changes can aggravate symptoms.

Adult-Onset Asthma

Adult-onset asthma differs from childhood asthma.

Characteristics include:

onset after age 20–30
less association with childhood allergies
more persistent symptoms
higher likelihood of severe disease

Occupational exposure and hormonal changes contribute to adult-onset asthma.

Risk Factors for Asthma in Adults

Several factors increase asthma risk:

long-term exposure to pollution
smoking or passive smoking
occupational chemicals or dust
obesity
family history of asthma
chronic sinusitis or allergies

Women may experience asthma onset or worsening during hormonal changes.

When Asthma Symptoms Become Serious

Seek immediate medical attention if experiencing:

severe breathlessness
difficulty speaking in full sentences
bluish lips or fingertips
rapid worsening of symptoms
poor response to usual inhalers

These signs indicate a potentially life-threatening asthma attack.

How Adult Asthma Is Diagnosed

Diagnosis includes:

detailed symptom history
physical examination
lung function tests (spirometry)
response to bronchodilators

Early diagnosis improves long-term outcomes.

Impact of Untreated Asthma

Untreated asthma can lead to:

frequent attacks
reduced lung function
sleep disturbances
missed workdays
reduced quality of life

According to Lancet respiratory studies, uncontrolled asthma increases hospitalisation risk.

Managing Asthma Symptoms in Adults

Effective asthma management focuses on:

identifying and avoiding triggers
using prescribed inhalers correctly
monitoring symptoms regularly
maintaining follow-up care

Asthma action plans help patients recognise worsening symptoms early.

Role of Preventive Healthcare

Preventive healthcare helps:

detect asthma early
assess lung function
guide lifestyle modifications

Regular health checkups are especially important for individuals with respiratory symptoms or occupational exposure.

Lifestyle Measures That Support Asthma Control

Helpful practices include:

avoiding smoking
improving indoor air quality
wearing masks in polluted environments
maintaining healthy weight
regular, moderate exercise

Lifestyle support complements medical treatment.

Mental Health and Asthma

Stress and anxiety can worsen asthma symptoms.

Stress management:

reduces symptom frequency
improves medication response

Holistic care improves asthma outcomes.

Importance of Medication Adherence

Asthma medications work best when:

taken regularly as prescribed
inhaler technique is correct

Skipping treatment increases flare-up risk.

Long-Term Outlook for Adults With Asthma

With proper management:

symptoms are well controlled
severe attacks are preventable
normal activity levels are achievable

Most adults with asthma lead active, productive lives.

Conclusion

Asthma symptoms in adults are often subtle, variable and easily mistaken for common respiratory problems. Wheezing, breathlessness, chest tightness and chronic cough should not be ignored, especially when triggered by pollution, exercise or weather changes. Early diagnosis, trigger control and consistent treatment are essential to prevent severe attacks and preserve lung health. Recognising adult asthma early empowers individuals to manage symptoms effectively and maintain a good quality of life.

References

Indian Council of Medical Research (ICMR) – Respiratory Disease and Asthma Studies
World Health Organization (WHO) – Asthma Management and Prevention Guidelines
National Family Health Survey (NFHS-5) – Respiratory Health Indicators
Lancet Respiratory Medicine – Adult Asthma Outcomes and Management
NITI Aayog – Air Pollution and Respiratory Health Reports
Statista – Global Asthma Prevalence and Trends

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