The COVID-19 pandemic may be over, but our immune systems are still feeling the impact. After years of battling constant viral threats, from COVID-19 to seasonal flu and other infections, our body’s defense system is exhausted. Many people continue to experience lingering inflammation, frequent illnesses, and slower recovery times. This extended state of immune stress has compromised us further to chronic illness, including autoimmune diseases and even neurodegenerative diseases such as Parkinson's. So why is our immune system still in trouble? And how do we give it its power back? Understanding immune exhaustion is the beginning of rebuilding our body's natural immunity.

A weakened immune system makes people more susceptible to disease, mental illnesses, and even sleep disorders. Now, new research indicates that immune system depletion may play an important role in the onset of Parkinson's disease, a degenerative neurologic disorder that compromises movement and cognition.

Role of Inflammation in Parkinson's Disease

Dysfunctional immune response is a leading cause of long-standing inflammation within the body, that has been found to contribute towards a multitude of conditions, including cardiovascular conditions, diabetes, depression, and neurodegenerative diseases such as Alzheimer's.

As people age, their immune system naturally becomes less effective. This deterioration, referred to as immune exhaustion, may be a key contributor to the onset and progression of Parkinson’s disease. Rebecca Wallings, a Parkinson’s Foundation Launch Award grant recipient and senior postdoctoral fellow at the University of Florida, believes that an accumulation of exhausted immune cells could be driving neurodegeneration in Parkinson’s patients.

How a Tired Immune System Might Affect Parkinson's?

Parkinson's disease is most commonly linked with the degeneration and loss of dopaminergic neurons—motor nerve cells that produce dopamine, an essential neurotransmitter for movement. While researchers have long suspected inflammation is involved in this neurodegeneration, the mechanisms are not yet well understood.

Wallings' study is on immune cell exhaustion, a process by which aging immune cells fail to control immune responses effectively. Her research indicates that instead of dampening inflammation in Parkinson's patients, attempts should be made to rejuvenate the immune system to regain its functionality.

Energy Deficiency in Immune Cells

One of the major findings of Wallings' work is the function of mitochondrial impairment in immune cell exhaustion. Mitochondria are commonly called the powerhouses of cells, as they are vital for generating energy. As mitochondria age and become inefficient, immune cells fail to function well, potentially accelerating neurodegeneration in Parkinson's disease.

Wallings has found that mutations in the LRRK2 gene, a recognized genetic risk factor for Parkinson's disease, are linked with defective mitochondrial function and immune cell exhaustion. Her current work includes testing various therapeutic approaches to restore mitochondrial function in immune cells with the potential to enhance the immune system and potentially prevent or treat Parkinson's disease.

Will Rejuvenating the Immune System Help in Treatment?

For decades, the standard practice in treating Parkinson's has been to suppress brain inflammation. Yet Wallings' work indicates that instead of slowing down immune responses, restoring the immune system could be a more successful strategy. By addressing mitochondrial impairment and immune resilience, researchers can potentially reverse or slow down Parkinson's disease.

Wallings is now looking into how to rejuvenate immune cells by fixing mitochondria. She studies immune cells from patients with Parkinson's as well as from healthy subjects and performs experiments on animal models to determine if rejuvenation of the immune system could result in improved disease outcomes.

Lifestyle Factors That May Affect Parkinson's Risk

While there is no cure for Parkinson's disease, some lifestyle adjustments may decrease the chances of developing the illness. Since neurodegenerative diseases are associated with chronic inflammation and immune dysfunction, developing habits that enhance immune function might prove helpful.

Diet: There is evidence to suggest that eating in accordance with the Mediterranean or MIND diets, both high in antioxidants, healthy fats, and anti-inflammatory foods, can encourage brain wellness and reduce Parkinson's risk.

Avoiding Dangerous Substances: Restricting alcohol and nicotine use can maintain a robust immune system and suppress inflammation.

Reducing Stress: Chronic stress weakens immune function, so methods such as meditation, exercise, and sufficient sleep can lead to improved overall well-being.

Pope Leo XIV’s lung cancer diagnosis has raised questions about whether a lung nodule always signals cancer.

The 71-year-old pontiff announced in a post on X this week that doctors had detected a small, localized lung nodule during medical examinations. The nodule was detected at a very early stage, and doctors recommended surgery to remove it.

According to Vatican News, surgeons at Gemelli Hospital removed the lower lobe of his right lung using a video-assisted technique. Examination of the tissue confirmed lung adenocarcinoma, the most common subtype of non-small cell lung cancer (NSCLC), accounting for roughly 40% of lung cancer cases.

“An intraoperative histological examination confirmed the diagnosis of lung adenocarcinoma, as suspected from the preoperative examinations,” the statement said.

But does finding a lung nodule always mean cancer? HealthandMe spoke to experts to understand which nodules need further investigation and what warning signs to watch for.

What Is a Lung Nodule?

Also read: Pope Leo XIV Will Undergo Lung Nodule Surgery: When Does Removal Become Necessary

A lung nodule is a small, localized spot in the lung, usually detected during a chest X-ray or CT scan. Most are benign, but some may indicate early lung cancer.

Dr Dipanjan Panda, Senior Consultant, Medical Oncology, Indraprastha Apollo Hospital, Delhi, told HealthandMe, that lung nodules can develop for several reasons, including infections, inflammation and, in some cases, cancer.

Does a Lung Nodule Mean Cancer?

Doctors assess a nodule’s size, shape, density and growth, along with the patient's age, smoking history and other risk factors. Depending on these findings, they may recommend follow-up CT scans, PET-CT imaging or a biopsy.

“A lung nodule is not synonymous with cancer. Most nodules are benign, often related to previous infections or scarring. Their size, appearance, growth, and the patient’s risk factors determine whether surveillance with repeat CT, PET-CT, or biopsy is needed. The key is appropriate risk assessment, not panic or unnecessary testing,” Dr Karn Mehra, Senior Consultant and Unit Head, Advanced Lung Failure and Transplant Pulmonologist, Fortis Hospital, Manesar, told HealthandMe.

When Should You Worry About A Lung Nodule?

Read More: Lung Nodule on CT Scan? Doctors Explain When You Should Worry

Dr Raajit Chanana, Director and Senior Consultant, Medical Oncology, Dharamshila Narayana Superspeciality Hospital, Delhi, highlighted several factors that may raise concern about malignancy:

• Size: Larger nodules generally carry a higher risk of malignancy.
• Growth: An enlarging nodule warrants further evaluation, while stability over time can be reassuring.
• Appearance: Irregular or spiculated edges are more concerning than smooth, well-defined borders.
• Smoking history: Current and former smokers face a higher risk of lung cancer.
• Personal and environmental factors: A previous cancer diagnosis, family history of lung cancer, and exposure to asbestos or radon may increase concern.
• Persistent cough, coughing up blood, unexplained weight loss, chest pain or breathlessness should prompt medical evaluation.

Can Lung Cancer Affect Non-Smokers?

Although tobacco remains a major risk factor, lung cancer can also develop in people who have never smoked.

Dr Mehra noted that lung cancer in never-smokers is increasingly being recognized, including among younger adults. Air pollution, occupational exposures and genetic susceptibility may also contribute to the risk.

However, living in a polluted city alone does not justify annual CT scans. Screening should follow established risk criteria, particularly those based on age and smoking history. Low-dose CT can detect early lung cancer in eligible high-risk individuals, while indiscriminate scanning can lead to radiation exposure, false-positive results and unnecessary procedures.

What Happens After a Lung Cancer Diagnosis?

READ: Dry Cough, Breathlessness May Not Always Be Asthma — Could It Be ILD?

Once lung cancer is confirmed, doctors determine its subtype, stage and molecular profile to guide treatment. Depending on these findings, treatment may include surgery, radiotherapy, targeted therapy, immunotherapy or chemotherapy.

For nodules not confirmed as cancer, management depends on their size, appearance, growth and the patient's risk factors. Small, low-risk nodules may require periodic CT scans, while suspicious ones may need further imaging or a biopsy. Not every nodule requires an invasive procedure.

Why Is Follow-Up Important?

“A lung nodule is not a cancer diagnosis, but it should never be ignored. Completing recommended follow-up scans is crucial. Quitting smoking remains one of the most effective ways to reduce lung cancer risk. Long-term smokers aged 50 and above should discuss whether they qualify for annual low-dose CT screening,” Dr Chanana said.

Short-term exposure to air pollution may increase the risk of hospitalisation for several serious health conditions, including cancers and mental disorders, according to a new landmark multicountry study published in The Lancet Planetary Health.

Researchers analysed 346.5 million hospitalisation records from 949 communities across six countries and territories, which included Australia, Brazil, Canada, Chile, New Zealand and Taiwan.

The study examined the relationship between short-term exposure to fine particulate matter (PM2.5) and hospital admissions between 2000 and 2019.

The findings revealed that every 10 micrograms per cubic metre (μg/m³) increase in PM2.5 concentration was associated with an 8% higher risk of hospitalisation from any cause. It was the strongest for malignant neoplasms, or cancers, followed by mental disorders.

The researchers also found that the increased risks associated with short-term exposure could persist for up to 21 days.

Hospital Admissions Related To Cancer And Mental Health Increased

Also read: Can Delhi’s Air Pollution Increase GI Cancer Risk? Doctors Report Patients As Young As 15

Among the disease categories examined, malignant neoplasms showed the strongest association with short-term PM2.5 exposure, with a 10.8% higher risk of hospitalisation for every 10 μg/m³ increase in particulate matter concentration.

It was followed by mental disorders, which showed a 10% higher risk. Other neoplasms were linked with a 9.6% increase, while nervous system diseases showed an 8.5% increase.

Respiratory diseases, that were commonly prevalent with air pollution, showed a 6.7% increase in hospitalisation risk.

These findings suggest that the health consequences of polluted air may not just be limited to lungs. They could affect people with a wide range of medical conditions.

However, the researchers assessed hospital admissions, not the occurrence of new diseases. Hence, they found that increases in PM2.5 exposure could increase the likelihood of hospitalisation among people affected by these conditions.

Decline In Hospitalisation Risks

Also read: Delhi Smog: Can You Really Tackle Pollution Season With An N95 Mask And Air Purifier?

The researchers found that hospitalisation risks related to pollution were lower during 2010-2019 than in 2000-2009. Using the World Health Organization's daily PM2.5 guideline of 15 μg/m³ as a reference, the estimated proportion of hospitalisations due to exposure declined from 8.9% to 3.9% between the two decades.

Despite this improvement, the associations remained significant across all disease categories. The study had limitations, including substantial differences in effects across different countries and territories. Its findings also cannot automatically be generalised to regions that were not included, including India.

The researchers concluded that reducing PM2.5 exposure remains an important public health measure to lower hospitalisation risks. Cleaner transport, stricter industrial emission controls and lower reliance on polluting fuels could help limit exposure and the significant health burden that comes with it.

The researchers also said that the effects of short-term PM 2.5 exposure on hospital admissions could persist for up to 21 days after exposure.

Effects Of PM2.5

PM2.5 refers to fine particulate matter measuring 2.5 micrometres or less in diameter. These particles can come from vehicle exhaust, industrial emissions, construction activities, power generation and the burning of fuels and biomass.

Because of their small size, PM2.5 particles can penetrate deep into the lungs, with some components entering the bloodstream. Exposure can trigger inflammation and oxidative stress, potentially affecting multiple organs.

Despite the observation, the study does not prove that short-term exposure to air pollution increases the risk of serious diseases like cancer. Stronger air-quality monitoring, improved cancer registries and studies linking data with clinical results could help researchers assess whether pollutants are associated with specific cancer types.

Studies would also need to account for other risk factors and differences in exposure across populations.

India faces a substantial hepatitis C burden, with the World Health Organization (WHO) estimating that 5.5 million to 12 million people are living with chronic hepatitis C virus (HCV) infection.

Untreated chronic HCV infection can lead to liver scarring, cirrhosis and liver cancer. Could shortening treatment by four weeks help more patients access a cure?

A multi-center trial led by researchers from the Indian Council of Medical Research (ICMR) found that an eight-week course of a commonly used antiviral combination was as effective as the standard 12-week regimen in patients without cirrhosis. Published in The Lancet, the findings could have implications for treatment costs and access to care.

The treatment combines sofosbuvir (400 mg) and velpatasvir (100 mg), two direct-acting antivirals that target the hepatitis C virus.

What Did The Indian Trial Find?

Also read: Punjab To Start Screening For HIV, Hepatitis B & C At De-Addiction Centres

The RESOLVE trial, led by researchers from Sanjay Gandhi Postgraduate Institute of Medical Sciences (SGPGIMS), Lucknow, evaluated whether eight weeks of sofosbuvir and velpatasvir could match the effectiveness of the standard 12-week course.

The trial enrolled 880 patients without cirrhosis across five publicly funded hospitals in Lucknow, New Delhi and Varanasi. Half received the combination for eight weeks, while the other half received it for 12 weeks.

Among participants who completed treatment and follow-up, 98.8% in the eight-week group achieved a sustained virological response, compared with 99% in the 12-week group. This means the virus remained undetectable after treatment, indicating a cure.

The researchers found that the shorter regimen was non-inferior to the standard course, meaning it was not less effective beyond the trial's prespecified statistical margin.

The study also reported no drug-related serious adverse events or treatment discontinuations due to adverse events.

How Shorter Treatment Help Reduce Hepatitis C Burden In India?

Direct-acting antivirals transformed hepatitis C treatment nearly a decade ago, making it possible to cure most patients with relatively few side effects. However, treatment costs and access remain important considerations for large public health programmes.

A 12-week course of sofosbuvir and velpatasvir costs approximately ₹15,000. Shortening treatment by four weeks could save around ₹5,000 per patient.

If adopted for a population of 60 lakh people requiring treatment, the shorter regimen could potentially save ₹3,000 crore. However, these are projected savings, and the actual impact would depend on patient eligibility, treatment costs and adoption in clinical practice.

Who Can Receive The Shorter Treatment?

The findings apply to patients without cirrhosis, as the trial excluded those with the condition. Patients with cirrhosis may require different treatment approaches depending on the severity of their liver disease and other clinical factors.

The trial's results do not mean that everyone with hepatitis C can switch to an eight-week course. Further evaluation and changes to relevant clinical guidance may be needed before the shorter regimen becomes routine practice.

Patients should consult their treating physician before making any changes to their prescribed treatment.

How Does Hepatitis C Spread?

Hepatitis C can cause illness ranging from mild infection to serious, long-term liver disease. Although some acute infections resolve spontaneously, chronic infection can progress to cirrhosis and hepatocellular carcinoma, a type of liver cancer.

The virus can spread through infected blood, including via shared needles and unscreened blood transfusions.

Perinatal transmission is an important route of HCV acquisition in children. Early detection can help identify infected infants and ensure appropriate follow-up.