First coughing, now diarrhea: this is how the corona symptoms have changed over time

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When Corona broke out, it was clear to most people that if you coughed or lost your sense of smell and taste, you could get an infection. But a lot has changed since then. Numerous new variants have had a significant impact on the virus and the course of the disease.

Scientists are currently mainly concerned with the JN.1 variant, which first appeared in France in September. It is responsible for a large proportion of current new infections worldwide – and in some cases is barely distinguishable from normal flu.

“When Covid first appeared it was characterized by these very strange, vague symptoms. Now I feel it has mutated into flu-like symptoms, making it clinically very difficult to distinguish between the two,” Ziad Tukmachi, a GP at Chartfield Surgery in south-west London, told the BBC. So has Covid become less dangerous?

The population has better immune protection

“The virus is not necessarily less pathogenic,” Greg Towers, professor of molecular virology at University College London, emphasized to the broadcaster. “Rather, it infects a population that is less likely to get sick because they have already experienced Sars-CoV-2.” Although there was no Covid immune protection at the start of the pandemic, the majority of the population has now been infected and has developed a defense mechanism.

According to Denis Nash, epidemiologist at the City University of New York, those who have so far been spared from Covid are especially at risk: “There are still people who have somehow managed to be completely Covid neutral to stay. If they are not vaccinated or are insufficiently vaccinated, they are at greatest risk of severe and long-lasting symptoms.”

New variants affect bodies differently

But the virus itself has also changed. For example, compared to other omicron subvariants, JN.1 has a better ability to evade the immune system. This ability brings other symptoms.

Researchers from Virginia Commonwealth University found that the chance of loss of sense of smell or taste in infections with ommicron-related variants is only about six to seven percent – ​​compared to the early pandemic phase. Instead, patients more often complain of diarrhea or headaches.

Tower explains why: “There has been a huge shift in viral tropism, i.e. which cells are infected. And that is determined by the sequence of the spike protein.” Because “almost everyone in the world” has already been infected or vaccinated, the virus is under “enormous pressure” to evade immune responses, meaning the spike protein has evolved significantly. “This causes it to infect different cells to gain access, preventing people from losing their sense of smell or taste.”

Risk of blood clots and Long Covid remains

However, a major risk of Corona remains that it can damage blood vessels and organs via micro clots. David Strain, professor of cardiometabolic health at the University of Exeter, warns: “We are seeing more microvascular complications and a gradual change in kidney function with the new JN.1 variant, which appears to be worse than previous variants.” According to the expert, it is unclear whether this is due to the variant or the fact that many people have not been vaccinated for a long time.

Because microclots can also be a possible cause of Long Covid diseases, this risk remains. Danny Altmann, professor of immunology at Imperial College London, explains: “Research from March to summer 2020 shows that the risk of developing Long Covid was around 10 percent. Now we have many more infections and the risk of Long Covid appears to have decreased – not because of a milder variant, but because of some protection from vaccine doses. (Mrs)

Source: Blick