<p>Behind many sudden deaths lie clots that block blood flow to the heart, lungs, or brain. Globally, blood clots are linked to one in four deaths, which is more than AIDS, breast cancer, and traffic accidents combined. </p><p>In India, they tend to strike earlier than in Western countries, often during people’s most productive years. Every year, more than 2.5 million Indians die from heart-related causes, with clotting a major factor.</p><p>Yet the issue remains largely invisible in India’s public health agenda. The warning signs are easy to miss: pain in the chest or severe headache, swelling in a leg, or unexplained breathlessness or dizziness. Left untreated, this can lead to sudden death.</p><p>A stronger focus on prevention and early detection could turn the tide against this silent killer.</p>.Cycle of privilege: Why India votes for dynasty.<p>After viral infections, the risk of serious clotting remains high. The Covid-19 pandemic revealed that infections can make blood more prone to clotting by damaging blood vessels, activating platelets — tiny cell fragments that help form clots — and triggering inflammation. During the pandemic, the D-dimer test, which measures fragments of clots circulating in the blood, also became widely known as a way to detect abnormal clotting.</p><p>Public concern about clots has since faded, but the threat persists. Dangerous clots are often the hidden cause of heart attacks, strokes, and blocked veins in the legs or lungs. These conditions, collectively known as venous thromboembolism, cover two related problems: deep vein thrombosis, when a clot forms in a deep vein (often in the leg), and pulmonary embolism, when that clot travels to the lungs. Both can recur, and cause sudden death or lead to lasting organ damage.</p><p>Evidence suggests that vaccination helps protect against severe illness and long Covid by maintaining immunity. However, rare cases of a condition called thrombosis with thrombocytopenia syndrome — a combination of clotting and unusually low platelet counts — were linked to the AstraZeneca and Johnson & Johnson vaccines, occurring in about 10 people per million doses. mRNA-based vaccines from Pfizer and Moderna have not shown this effect. </p><p>Experts agree that the benefits of vaccination far outweigh the small risk of such rare side effects.</p><p>The risk of clotting rises among people who are sedentary, obese, diabetic, recovering from surgery or trauma, or undergoing cancer treatment. Women face added risk during pregnancy or while using oral contraceptives, as hormone changes can make blood thicker. Some families carry genetic mutations that make their blood more likely to clot.</p><p>Geography can also play a role. Soldiers stationed at high altitudes in Siachen and Ladakh, and pilgrims trekking to Amarnath or Kailash Mansarovar, face conditions such as low oxygen, dehydration, and extreme cold that increase clotting risk.</p><p><strong>Prevention and new cures</strong></p><p>The good news is that prevention is simple: move more, sit less, and stay hydrated. Standing or walking every hour, even during long flights or hospital stays, helps maintain circulation.</p><p>Treatment options have also advanced. Blood thinners or anticoagulants remain the main line of defence. Older drugs such as heparin and warfarin have long been used to stop new clots from forming. </p><p>Newer oral anticoagulants act more precisely on the body’s clotting process. Direct thrombin inhibitors such as dabigatran block thrombin, the key enzyme that builds clots, while other inhibitors like rivaroxaban target another crucial step.</p><p>India has made its own mark in this field. The Council of Scientific and Industrial Research developed the clot-busting enzyme streptokinase, introduced in 2009, which dissolves existing clots. New recombinant, or laboratory-engineered, versions are now being tested. A next generation of drugs that block factor XI, another clotting protein, could offer safer long-term options.</p><p>Around the world, scientists are also working on faster, more accurate diagnostic tools. Handheld devices and new urine-based tests can detect abnormal clotting within minutes. Indian researchers have created innovations such as the Indian Institute of Science’s nanozyme — a microscopic enzyme mimic that prevents clots — and IIT (BHU)’s nanoparticles designed to deliver anti-clot drugs directly where they are needed.</p><p>The Defence Research and Development Organisation (DRDO) has developed a diagnostic test using microRNA-145, a small molecule in the blood that helps regulate gene activity and is linked to clot formation. This was later validated in Europe’s Trøndelag Health Study. Wearable ultrasound devices and smart biosensors could soon make detection faster, safer, and more accessible.</p><p>Because clot treatment can be expensive and long-term, prevention remains far more cost-effective. Many cases arise during predictable hospital stays or cancer treatment.</p><p>In 2008, the US Surgeon General made clot prevention a national priority, prompting hospitals to use checklists and discharge guidelines that have saved thousands of lives. India has begun similar efforts. The Indian Council of Medical Research (ICMR) launched the country’s first hospital-based registry, i-RegVeD, in 2022, collecting real-time data from 16 tertiary hospitals. Early results from more than 2,800 patients show high recovery rates and about 3% mortality.</p><p>The National Academy of Medical Sciences’ 2024 task-force report recommends routine hospital risk checks to detect clots early. These initiatives could help shape national policy and make care more evidence-based.</p><p>Despite strong public campaigns on diabetes and hypertension, awareness of blood clots remains minimal. It is rarely mentioned in schools, workplaces, or even in-flight safety briefings, though simple awareness could save thousands of lives. A co-ordinated public campaign through social media, airlines, pilgrimage organisers, and hospitals could make a critical difference.</p><p>Clots can be fatal but are largely preventable. Early recognition, timely medical care and sustained awareness can help India tackle this silent killer.</p><p>Mohammad Zahid Ashraf is Dean, Faculty of Life Sciences, Jamia Millia Islamia and a Fellow of all three of India’s National Science Academies.</p><p>This article was first published under Creative Commons by 360info.</p><p><em>Disclaimer: The views expressed above are the author's own. They do not necessarily reflect the views of DH.</em></p>
<p>Behind many sudden deaths lie clots that block blood flow to the heart, lungs, or brain. Globally, blood clots are linked to one in four deaths, which is more than AIDS, breast cancer, and traffic accidents combined. </p><p>In India, they tend to strike earlier than in Western countries, often during people’s most productive years. Every year, more than 2.5 million Indians die from heart-related causes, with clotting a major factor.</p><p>Yet the issue remains largely invisible in India’s public health agenda. The warning signs are easy to miss: pain in the chest or severe headache, swelling in a leg, or unexplained breathlessness or dizziness. Left untreated, this can lead to sudden death.</p><p>A stronger focus on prevention and early detection could turn the tide against this silent killer.</p>.Cycle of privilege: Why India votes for dynasty.<p>After viral infections, the risk of serious clotting remains high. The Covid-19 pandemic revealed that infections can make blood more prone to clotting by damaging blood vessels, activating platelets — tiny cell fragments that help form clots — and triggering inflammation. During the pandemic, the D-dimer test, which measures fragments of clots circulating in the blood, also became widely known as a way to detect abnormal clotting.</p><p>Public concern about clots has since faded, but the threat persists. Dangerous clots are often the hidden cause of heart attacks, strokes, and blocked veins in the legs or lungs. These conditions, collectively known as venous thromboembolism, cover two related problems: deep vein thrombosis, when a clot forms in a deep vein (often in the leg), and pulmonary embolism, when that clot travels to the lungs. Both can recur, and cause sudden death or lead to lasting organ damage.</p><p>Evidence suggests that vaccination helps protect against severe illness and long Covid by maintaining immunity. However, rare cases of a condition called thrombosis with thrombocytopenia syndrome — a combination of clotting and unusually low platelet counts — were linked to the AstraZeneca and Johnson & Johnson vaccines, occurring in about 10 people per million doses. mRNA-based vaccines from Pfizer and Moderna have not shown this effect. </p><p>Experts agree that the benefits of vaccination far outweigh the small risk of such rare side effects.</p><p>The risk of clotting rises among people who are sedentary, obese, diabetic, recovering from surgery or trauma, or undergoing cancer treatment. Women face added risk during pregnancy or while using oral contraceptives, as hormone changes can make blood thicker. Some families carry genetic mutations that make their blood more likely to clot.</p><p>Geography can also play a role. Soldiers stationed at high altitudes in Siachen and Ladakh, and pilgrims trekking to Amarnath or Kailash Mansarovar, face conditions such as low oxygen, dehydration, and extreme cold that increase clotting risk.</p><p><strong>Prevention and new cures</strong></p><p>The good news is that prevention is simple: move more, sit less, and stay hydrated. Standing or walking every hour, even during long flights or hospital stays, helps maintain circulation.</p><p>Treatment options have also advanced. Blood thinners or anticoagulants remain the main line of defence. Older drugs such as heparin and warfarin have long been used to stop new clots from forming. </p><p>Newer oral anticoagulants act more precisely on the body’s clotting process. Direct thrombin inhibitors such as dabigatran block thrombin, the key enzyme that builds clots, while other inhibitors like rivaroxaban target another crucial step.</p><p>India has made its own mark in this field. The Council of Scientific and Industrial Research developed the clot-busting enzyme streptokinase, introduced in 2009, which dissolves existing clots. New recombinant, or laboratory-engineered, versions are now being tested. A next generation of drugs that block factor XI, another clotting protein, could offer safer long-term options.</p><p>Around the world, scientists are also working on faster, more accurate diagnostic tools. Handheld devices and new urine-based tests can detect abnormal clotting within minutes. Indian researchers have created innovations such as the Indian Institute of Science’s nanozyme — a microscopic enzyme mimic that prevents clots — and IIT (BHU)’s nanoparticles designed to deliver anti-clot drugs directly where they are needed.</p><p>The Defence Research and Development Organisation (DRDO) has developed a diagnostic test using microRNA-145, a small molecule in the blood that helps regulate gene activity and is linked to clot formation. This was later validated in Europe’s Trøndelag Health Study. Wearable ultrasound devices and smart biosensors could soon make detection faster, safer, and more accessible.</p><p>Because clot treatment can be expensive and long-term, prevention remains far more cost-effective. Many cases arise during predictable hospital stays or cancer treatment.</p><p>In 2008, the US Surgeon General made clot prevention a national priority, prompting hospitals to use checklists and discharge guidelines that have saved thousands of lives. India has begun similar efforts. The Indian Council of Medical Research (ICMR) launched the country’s first hospital-based registry, i-RegVeD, in 2022, collecting real-time data from 16 tertiary hospitals. Early results from more than 2,800 patients show high recovery rates and about 3% mortality.</p><p>The National Academy of Medical Sciences’ 2024 task-force report recommends routine hospital risk checks to detect clots early. These initiatives could help shape national policy and make care more evidence-based.</p><p>Despite strong public campaigns on diabetes and hypertension, awareness of blood clots remains minimal. It is rarely mentioned in schools, workplaces, or even in-flight safety briefings, though simple awareness could save thousands of lives. A co-ordinated public campaign through social media, airlines, pilgrimage organisers, and hospitals could make a critical difference.</p><p>Clots can be fatal but are largely preventable. Early recognition, timely medical care and sustained awareness can help India tackle this silent killer.</p><p>Mohammad Zahid Ashraf is Dean, Faculty of Life Sciences, Jamia Millia Islamia and a Fellow of all three of India’s National Science Academies.</p><p>This article was first published under Creative Commons by 360info.</p><p><em>Disclaimer: The views expressed above are the author's own. They do not necessarily reflect the views of DH.</em></p>
