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Published on: Jul 07, 2020
1 minute read
By: Dr Rajan Choudhary

Asymptomatic Carriers Of COVID

Why Asymptomatic carriers of COVID are as dangerous as symptomatic patients

Many countries have now begun enforcing masks for everyone to wear when out in public, in enclosed spaces, or on public transport. There is good evidence to support these measures, but unfortunately, some still show resistance to the idea. Whilst some reasons put forward are non-sensical (masks do not cause any noticeable or measurable decrease in oxygen delivery to the body), other people feel like they shouldn’t wear a mask because they do not have symptoms of COVID. And thus would not spread anything. Here we look at a recent publication in Nature, one of the most esteemed peer-reviewed scientific journals in the world, and what it shows us about the transmission of COVID in a population.

This study by Lavezzo et al looked at the suppression of the SARS-CoV-2 outbreak in the Italian municipality of Vo’. This municipality is 50 kilometers west of Venice with a population of just 3,416 people. It experienced its first casualty of COVID on the 21st of February, after which it underwent lockdown for 14 days. During this time data was collected on the clinical presentation and hospitalization of COVID patients, as well as other citizens through the contact tracing network.

In total 2,812 residents were tested in late February, with another 2,343 tests performed two weeks later at the end of lockdown. Nasal and throat swabs were taken to identify infected individuals. The study found only 2.6% of people were positive for COVID at the start of lockdown, which reduced to 1.2% two weeks later.

Out of this infected population, 42.5% were asymptomatic. They had no symptoms at the time of swab testing nor did they develop symptoms afterwards. When the viral load was measured between symptomatic and asymptomatic patients, there was little difference.

Evidence has pointed to a large asymptomatic population, and previous studies have shown it to be as high as 50% in some cases. Many would assume if a patient has no symptoms then they must have fought the infection before it became an issue, or had a very low viral load and therefore were not likely to spread it. This study shows it is simply not true. Asymptomatic carriers of COVID are likely to contribute to the transmission and spread of COVID amongst the population.

If you are asymptomatic you have as high a viral load as someone who is symptomatic. But there is no way to tell without a swab. You have as much of a potential to spread the infection to the vulnerable. Even in people who became symptomatic the height of transmission was found to be before the patient showed any symptoms.

So what does this mean? If you have COVID you are likely to spread it before you show any symptoms or any symptoms at all. We know masks are effective at significantly reducing the spread of COVID, by catching the water droplets that carry the SARS-CoV-2 Virus. Now that shops and public places are re-opening, the risk of spread is high.

Wear a mask. Stop the spread.

https://www.nature.com/articles/s41586-020-2488-1_reference.pdf suppression of a SARS article

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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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