Covid’s long -term influence on the lungs, intestines, brain and more

Five years-and hundreds of millions of cases-how the World Health Organization has announced the Covid-19 pandemia, scientists get a more pronounced picture of how the virus can affect the body long after it seems that the infection seems.

Some Covid’s effects became perceptible shortly after the virus began to spread. We quickly understood how fatal infection can be, especially in the case of people with basic diseases such as diabetes and heart disease. But it took years of research to start understanding how Covid’s fight can lead to enduring, sometimes imperceptible changes in different parts of the body.

Some of these effects, such as chronic fatigue and cerebral fog, are considered a long Covid, defined as symptoms of infections that persist for at least three months. According to some estimates, 400 million people around the world have been diagnosed. But the infection can also lead to other problems, including lung and heart damage, as well as changes in the microbiome in the intestines, which can not always be recognized as a long Covid, but it can still have a lasting effect on our health.

We now have a better sense of what can be with these changes, including the role of universal inflammation that Covid can cause. For most people, the inflammation disappears after cleaning the virus. But for some, if it “goes crazy” too intensively or stays as a “leisurely burn” for too long, it can sow havoc around the body, said Dr. Braden Kuo, a neurogastroenterologist at Massachusetts General Hospital.

Here’s what scientists have learned so far about inflammation and other factors that drive these effects.

Lungs

Covid irritates the lungs and can cause long -term problems, such as persistent breath and coughing. In scarce cases, Covid can lead patients to the development of pneumonia and leaving scars and compact tissue masses, called bumps, in the lungs. These scars can make breathing complex. Small studies It suggested that over 10 percent of people hospitalized with Covid infection had lung scars and other problems two years later.

Cause: The virus attacks Cells along the respiratory tractcausing inflammation that can attack and sometimes destroy vigorous lung tissue. This can disturb the lung ability to provide oxygen throughout the body, said Dr. Ziyad Al-Wyly, senior clinical epidemiologist at Washington University in St. Louis.

When the lungs try to recover and fix, they form scars. But the tissue of scars itself can stiffen the lungs and reduce the lung capacity, which leads to enduring symptoms such as cough and shortness of breath.

Bowel

Covid can cause brief -term symptoms such as nausea, vomiting and diarrhea.

But in some people Covid can lead to chronic gastrointestinal problems, such as reflux, constipation, diarrhea and abdominal pain. These problems can last months and even years. IN 2024 studyScientists estimated that Covid’s fighting left as many as 10 percent of people with enduring abdominal pain and 13 percent with gastrointestinal problems a year later.

Cause: Scientists do not know why Covid exactly can reject the normal function of the intestine so much – but they understand better what can be in the game. For example, it is now clear The virus can disrupt the intestinal microbiomeReduction of beneficial microorganisms and increasing the number of harmful. “Good” microorganisms can aid reduce inflammation, while “bad” can enhance them.

Inflammation of the infection itself, as well as from changed intestinal microorganisms, can harm the intestinal lining. This can allow toxins and broken food ingredients to escape from the intestine to other body tissues. Immune cells can then mount an allergy reaction to some foods, leading to food intolerance.

Inflammation can also “chew” nerves that signal pain in the intestines or which control intestinal cramps that maintain food movement, said Dr. Kuo. This can cause stomach or intestinal pain or make food move too quickly or too slowly through the digestive tract, causing symptoms such as diarrhea or constipation.

Brain

At the top of the infection, patients often develop headaches and feel dizzy and confused. Sometimes they try to find the right words, have difficulty concentrating or tracking conversations, or find that they have gaps in memory.

These symptoms may remain: research is roughly it showed 20 Down 30 percent From infected people, Covid experienced the cerebral fog at least three months after the initial infection. Studies also show that Covid can lead to states such as anxiety or depression or exacerbate existing mental health problems.

Cause: Scientists are still working on identifying all factors that contribute to lasting neurological problems after Covid. But one culprit seems clear: enduring inflammation that damages neurons and inhibits the creation of key connections between synapses. All this can cause symptoms such as described above. Some researchers also believe that the areas of the brain involved in cognition and emotions are particularly susceptible to inflammation, which helps to explain why the infection can cause or deteriorate problems with mental health.

Another theory is that the virus disrupts Blood-brain barrier, which protects brain tissue and is necessary for cognitive functions.

Fragments of the virus can also remain in the brain in a long -term perspective, which can explain why some cognitive symptoms continue outside the initial infection.

Heart

The Covid-19 infection increases the risk of heart problems, including heart attacks, impacts, myocardial damage and irregular heartbeat, called arrhythmia. One gigantic study showed that having a covid has doubled the risk of a sedate cardiovascular event for up to three years.

Cause: When you have an acute Covid infection, stress of fever and inflammation can put an excessive heart demand. In someone who already has the accumulation of plate in the arteries or heart muscle, which began to become stiff, the demand can lead to irregular heartbeat or heart attack.

But more common, as they think, is that the virus causes inflammation that hurts the heart muscles. The virus can also damage cells lining the blood vessels, which leads to inflammation. This can cause a fresh clot or cause that the existing plate breaks and clogs the blood vessel. This type of blockage can cause sudden death after a heart attack or lead to further damage to the heart muscles and other tissues, which may cause heart failure or arrhythmia.

People hospitalized due to Covid have the highest brief and long-term risk of heart complications. Some studies suggest that people with a blood group-a, B or AB-AB-AB-are particularly increased risk, perhaps because the blood group can be associated with this like blood clots.

Circulatory system

Studies of patients with long Covids show that their bodies have problems bringing blood from their legs and abdomen and returning to the heart. This can reduce the amount of blood that will inflate the heart, causing fatigue, shortness of breath and a sense of evil after exercise.

Cause: It is not clear why these circulatory problems occur, but scientists hypothesize that in some patients inflammation harms some nerve fibers outside the brain and the spinal cord, which regulate the ability to squeeze blood vessels. This can cause impairment of blood flow, said Dr. David Systrom, a pneumonian and critical doctor at Brigham and Women’s Hospital in Boston.

Dr. Systrom also said that in some patients with long Covid it seems that muscles are less able to extract oxygen from blood than normally, hindering their ability to keep up with exercises. In addition, mitochondria-urban-producing cell energy-not to work properly or fully, providing another hit to muscle tissue.