Sleep changes as we age. When we were kids, we needed 10 to 12 hours of sleep, for teens it is eight to 10 and it decreases to seven to nine as we reach adulthood. But there is always a lack of urgency when it comes to sleep and young adults, many of whom prefer staying up and doing different activities. According to the Centre of Disease Control and Prevention, many national surveys show that about 37% of men, and 39% of people from the age of 45 to 64 reported not getting enough sleep.

Many people in America don't sleep the right amount. This means they either sleep too long or not long enough. But what happens to your body when you do not sleep enough? You just feel tired right? No, when you don't get this much sleep, your body can get stressed. This can make you more likely to get sick. A study published by the JAMA Network Open Sleep Trajectories and All-Cause Mortality Among Low-Income Adults showed that people who don't sleep the right amount have a higher chance of dying early. It's like your body needs that time to rest and fix itself. Without enough good sleep, things can start to go wrong. So, getting the right amount of sleep is super important for staying healthy.

How Was The Study Done?

Scientists wanted to see how sleep habits affect people's health over many years. They looked at almost 47,000 people who were between 40 and 79 years old. They asked them about their sleep habits when the study started, and then again, a few years later. The scientists wanted to see if people's sleep habits changed. They divided people into groups based on if they started with too much or too little sleep, and if their sleep changed over time. For example, some people started sleeping a lot but then started sleeping very little. This helped the scientists see how different sleep patterns affected people's health. They wanted to see the long-term effects of sleep.

The study found that people who had sleep habits that changed a lot had a higher risk of dying early. This means if you started sleeping too much and then switched to sleeping too little, or the other way around, you were more likely to die sooner. They also found that these people had a higher risk of heart problems. The risks were even higher for some groups of people, like white adults and people with higher incomes.

Sleep Deprivation And Its Effect On The Body

If you often doze off when you are sitting and reading, watching a movie, talking to someone, sitting quietly after lunch or even during a few minutes of traffic, you may be sleep deprived according to the National Heart, Lung, and Blood Institute. They explain how sleep deprivation can cause issues with learning, focusing and reacting to certain things. The symptoms of sleep deprivation in kids differ a little as they might be overly active and have trouble paying attention to certain things. If you are experiencing sleep issues, make sure to speak to a healthcare professional who will help you identify the issues and direct you towards the treatment or changes you must make. Here are some ways sleep helps your body.

Repairs Your Heart

Good sleep allows your heart and blood vessels to heal. This keeps them strong and healthy, reducing the risk of heart problems.

Controls Hunger

Sleep helps balance your hunger hormones, so you don't feel too hungry. This helps prevent eating too much and keeps your weight healthy.

Manages Blood Sugar

Proper sleep helps your body use insulin correctly. This lowers the chance of high blood sugar, which can lead to diabetes.

Supports Growth

Deep sleep releases growth hormones, helping kids and teens grow. It also repairs body tissues, which is important for everyone.

Boosts Immunity

When you sleep well, your body's defense system gets stronger. This helps you fight off germs and stay healthy.

Climate change and rapid urbanization are changing mosquito habitats, and shifting dengue serotypes are reshaping the disease landscape in India. As a result, the country is now witnessing a transformation in how dengue spreads, who it affects, and how severe infections can become.

Once considered a seasonal monsoon illness, dengue is now increasingly becoming a year-round public health challenge, extending into hill states, semi-urban regions, and previously low-risk geographies.

In an exclusive interview with HealthandMe, Dr. Shikha Taneja Malik, Senior Scientific Affairs Manager, Drugs for Neglected Diseases initiative (DNDi), South Asia, discussed why India’s dengue numbers are likely being massively undercounted, how surveillance and diagnostic gaps are masking the real scale of the crisis, and why young adults are facing more severe infections due to changing serotypes.

Dr. Shikha also explained the urgent global push for affordable therapeutics and the challenges India still faces in developing an indigenous dengue vaccine despite its strong manufacturing capacity.

Here are the excerpts from the interview:

Q. Dengue was always called a monsoon disease. Is that label now dangerously misleading?

Dr. Shikha: Yes, I would argue that labels are not just outdated but risky, too. What we are seeing across India and across the region is a fundamental shift in the transmission pattern.

Dengue used to follow a fairly predictable seasonal curve — cases would spike between July and November, track the monsoon, and then recede. That curve is flattening. We are now seeing cases in February, March, and May — months that were previously considered safe. Delhi, Mumbai, Bengaluru — cities that used to have clear off-seasons for dengue — are reporting year-round transmission.

Warmer temperatures, altered rainfall patterns, unplanned urbanization, and poor sanitation have lengthened transmission seasons, making dengue a year-round systemic crisis. Models now predict year-round transmission in coastal regions, though monsoon months will retain the highest peak.

Also read: National Dengue Day 2026: India Reports 6,927 Cases And 10 Deaths In 2026

Q. Are serotype shifts driving changing dengue patterns, especially in young adults?

Dr. Shikha: Yes, India is witnessing active serotype shifts, and they directly explain rising severity, especially in young adults. Initial infection with one of the four dengue serotypes results in lifelong immunity to that specific serotype. Whereas, a secondary infection with a different serotype can trigger Antibody-Dependent Enhancement (ADE).

Young adults who were exposed to one serotype in childhood are now encountering a new dominant serotype, making them especially vulnerable to severe secondary infections.

Q. Is India undercounting dengue cases? Why do so many cases go unreported?

Dr. Shikha: The 2.89 lakh figure in 2023 is what our surveillance system captures, but it is almost certainly a fraction of the true burden. The Lancet has estimated that India accounts for around 33 per cent of the global dengue burden, and globally, we are looking at approximately 400 million infections every year. That puts India's real annual dengue burden potentially in the tens of millions — not hundreds of thousands.

Few studies have shown that the estimates of actual cases are approximately 282 times higher.

There are several reasons why cases go unreported, and they compound each other.

• A large proportion of infections are either asymptomatic or present as a generic fever — patients never seek formal care.
• Our surveillance system is passive and fragmented. Reporting is largely dependent on public health facilities.
• Confirmatory testing through NS1 antigen tests or PCR requires infrastructure that is not yet uniformly available at the primary health center level, particularly in rural and semi-urban areas.

Q. Are previously dengue-free regions in India now reporting cases due to climate change?

Dr. Shikha: Yes, the geographic spread is both significant and well-documented. Climate change is playing a major role in this shift. Rising temperatures, changing rainfall patterns, increasing humidity, and rapid unplanned urbanization are creating more favorable conditions for Aedes aegypti mosquitoes to survive and transmit the virus for longer periods each year.

Since the mid-1990s, dengue has rapidly spread to regions where it was historically non-existent, including Odisha, Arunachal Pradesh, and Mizoram. In the early 2000s, dengue was endemic only in a few southern and northern states; it has since spread to many states, including union territories.

Read More: Ebola Outbreak: Rare Bundibugyo Strain Confirmed In DR Congo And Uganda

The shift is particularly visible in hilly and cooler geographies such as Himachal Pradesh and Jammu & Kashmir. Climate modelling projects further expansion of Aedes albopictus into upper Himalayan regions, including Leh-Ladakh and Arunachal Pradesh, by 2050.

Q. What are the biggest challenges in indigenous dengue vaccine production in India?

Dr. Shikha: India has strong vaccine manufacturing capacity, but dengue remains scientifically complex. Existing vaccines have limitations and do not cover all vulnerable groups.

India’s first Phase 3 trial for an indigenous dengue vaccine, DengiAll, is underway across 18 states. The Butantan vaccine candidate, originally developed by NIH, has been licensed to Indian companies, including Panacea, SIIPL, and Indian Immunologicals, with the ICMR-Panacea candidate being the most advanced.

The recent DCGI approval of Qdenga is encouraging, but sustained financing and coordination between ICMR, DBT, and industry will be critical for developing a truly indigenous vaccine.

Dengue has become one of the fastest-emerging health crises in the urban parts of India. Every year during the monsoon season, the number of dengue cases rises dramatically in many Indian cities, posing a huge burden on the healthcare sector.

Though climate and mosquitoes are usually cited as reasons for the surge in dengue cases, the problem actually lies in how urban life and the infrastructure of the cities have changed over the decades.

Why Urban Areas Are More Vulnerable

The dengue virus is spread through the Aedes aegypti mosquito that lives well in fresh still water, which is abundant in urban areas.

Mosquitoes breed in construction sites, open water tanks, old plastic buckets, flower pots, coolers, water stored on roofs, and blocked drainage systems. Due to the growing size of cities and high population density, mosquito-borne diseases have become more common.

There are many factors that contribute to the rise in the number of dengue patients, one of which is unplanned city expansion. The fast pace of development in the cities results in stagnant water in the construction areas going unnoticed for weeks.

Moreover, improper drainage and a lack of sanitation facilities help mosquitoes breed. Even posh societies and offices can suffer if proper checks are not conducted.

Urban lifestyle trends also act as indirect factors contributing to the issue. Longer working hours, higher levels of indoor activities, and reliance on mechanical ventilation lead to less focus on environmental hygiene issues.

Families tend to take mosquito prevention steps only after an outbreak starts. The overuse of plastics and poor waste management practices in urban areas have exacerbated waterlogging problems.

The situation has been exacerbated by climate change and global warming. Mosquitoes can breed at a faster pace and survive for a longer period of time in the warm climate and unpredictable rain patterns. Another factor that plays an important role is urban heat islands, which refer to places that are hotter because of man-made concrete buildings.

What Needs to Change?

In order to curb the incidence of dengue, there must be an all-around transformation, both on the part of the governing authorities and the people. Firstly, urban planning should take into consideration good drainage facilities, frequent fogging, garbage disposal services, and proper regulation of building sites. Secondly, there must be frequent checks in residential areas, schools, offices, markets, and open public areas.

Secondly, the awareness campaign needs to be practical and more community-oriented. The citizens should realize that the prevention of dengue starts from their homes. Actions like washing the coolers once a week, covering the water tank, not allowing the water to stagnate, and using mosquito repellents will go a long way in minimizing the spread of dengue.

Early Detection and Healthcare Preparedness

Healthcare preparedness is also equally important. The early detection and proper treatment of dengue could help avoid any serious complications. One should never overlook symptoms like fever, body pain, headache, rashes on the skin, nausea, and weakness during the rainy season.

Combatting dengue fever is no longer just a matter of health care but rather a question of urban planning and lifestyle issues. As the cities continue to expand, everyone should unite and come up with healthier and more environmentally friendly cities. Otherwise, we may see more recurring problems of dengue outbreaks in urban settings every year.

Amid growing discussions around hantavirus transmission through body fluids, experts today stressed that cases involving transmission through breast milk or semen remain extremely rare and should not trigger unnecessary panic.

The discussions began after a 2023 study published in the journal Viruses found that the Andes strain of the rat-borne virus can persist in human semen for up to six years.

More concerning was the possibility that the virus could potentially be transmitted sexually even after a person has recovered, according to the peer-reviewed study.

The research, conducted by Swiss scientists at Spiez Laboratory, suggested that hantavirus may survive in the male reproductive tract like viruses such as Ebola.

“Taken together, our results show that the Andes virus has the potential for sexual transmission,” the study said. However, to date, no confirmed case of such transmission has been documented.

Why Viral RNA Can Persist In Semen

Speaking to HealthandMe, Dr. Rajeev Jayadevan, convenor of the IMA research cell, explained that the detection of Andes virus RNA — the hantavirus strain linked to the recent MV Hondius cruise ship outbreak — in semen long after recovery is not entirely unexpected.

“The finding of RNA belonging to the Andes virus in human semen long after recovery is no surprise. In fact, this is a well-described scenario in at least 27 different viruses, including Zika and Ebola,” he said.

He explained that viruses reaching the testis enter what is known as an “immune-privileged” site protected by the blood-testis barrier (BTB).

“The testis is naturally shielded from the body’s immune system to protect newly formed sperm cells from being recognised and destroyed as ‘foreign’,” Dr. Rajeev said.

According to the expert, many viruses take advantage of this natural immune protection, allowing them to remain in the area longer than expected.

However, he clarified that although researchers detected viral RNA in semen, the virus itself could not be cultured, meaning there is no proof that the infectious virus remained present.

Also read: Ebola Outbreak: Rare Bundibugyo Strain Confirmed In DR Congo And Uganda

Can Hantavirus Spread Via Breast Milk?

Another study published in Emerging Infectious Diseases, a monthly open-access peer-reviewed medical journal published by the US Centers for Disease Control and Prevention, highlighted the risk of mother-to-child transmission of the Andes strain of hantavirus through breast milk.

Andes virus (ANDV) is the only hantavirus known to spread between humans through close contact.

“We detected the genome and proteins of ANDV in breast milk cells from an infected mother in Chile who transmitted the virus to her child, suggesting gastrointestinal infection through breast milk as a route of ANDV person-to-person transmission,” the study said.

Epidemiologist Dr. Amitav Banerjee, professor at DY Patil Vidyapeeth, Pune, told HealthandMe that while isolated cases of hantavirus transmission from mother to child through breast milk have been reported, they are highly uncommon.

“These cases of hantavirus transmission through breast milk from mother to child are very rare. As a general rule, there is no need to worry excessively,” he said.

According to him, mothers experiencing fever during the acute stage of illness may temporarily avoid breastfeeding because viral load tends to be highest during active infection and just before symptoms appear. However, he stressed that breastfeeding should not be stopped routinely out of fear.

Dr. Amitav explained that the situation is somewhat comparable to HIV transmission through breast milk, which also occurs in less than 1 percent of cases. Despite that, mothers in many developing countries are still advised to continue breastfeeding because the health risks of depriving infants of breast milk are often greater than the risk of viral transmission.

He noted that hantavirus differs significantly from HIV because it is generally an acute and transient infection, unlike HIV, which persists lifelong in body fluids.

“Hantavirus infection is acute and transient, whereas HIV is lifelong,” he said, adding that hantavirus usually clears from the body after recovery, including from semen and other body fluids.

Sexual Transmission After Recovery Still Unclear

Dr. Rajeev noted that the Andes virus spreads primarily through close contact and shared personal space while a patient is symptomatic.

“Whether it can be sexually transmitted long after recovery remains unknown,” he said.

Overinterpreting RT-PCR Results

Dr. Amitav also cautioned against overinterpreting isolated reports of viral detection in semen or breast milk.

According to him, RT-PCR tests are extremely sensitive and may detect dead viral particles even after the infection has resolved. Therefore, a positive RT-PCR result does not necessarily mean that a person remains infectious.

“In fact, RT-PCR is highly sensitive and often used more for research and surveillance purposes. Detecting viral material does not always indicate active infection or transmission risk,” he said.

He added that hantavirus does not appear to persist as an infectious virus for a long period after recovery and that there is currently no strong evidence supporting long-term transmission once a patient has recovered.