Delta variant, how Covid-19 symptoms change

Some new clues seem to indicate that the symptoms of the delta variant of Sars-CoV-2 are slightly different and more difficult to distinguish from those of a normal cold.

(foto: Getty Images)

The list of symptoms of Covid-19 it is long and each patient is unique. Until now, however, we had learned about some red flags: the temperature, obviously; there fatigue; symptoms parainfluenza. But most of all anosmia e ageusia, or loss (respectively) ofsmell he was born in like, two of the most characteristic symptoms of the new disease from the very early stages of the pandemic. With the arrival of the delta variant, however, even these few certainties seem destined to collapse: according to a recent one English search the spread of the new viral strain has drastically changed even the most common symptoms of Covid 19, prompting several experts to ask to update the guidelines of the British Ministry of Health to reflect the new epidemic situation, and ensure the best chance of identifying in time any possible chain of transmission of the virus.

Many symptoms, few certainties

In fact, the definition of symptoms used in Great Britain to date it is rather limited, especially when compared to those provided by other major players in global health, like the WHO e i Centers for disease control and prevention Americans, and also to those established by ours Ministry of Health, based on the indications of European Center for Disease Prevention and Control (Ecdc). Where many health authorities indicate a list with almost one dozen symptoms to watch out for, the British National Health Service asks British citizens to pay attention to only three ailments, as a warning of a possible infection: high fever (over 37 and a half), cough and loss of taste / smell. A very short list, considered by many to be inadequate.

To reopen the company with the utmost speed and fairness, it is essential to improve our ability to control the transmission of the virus”, writes on Bmj a group of British public health specialists: “And to do that, you start with one wider and more appropriate definition of Covid symptoms to the context in which we operate, to arrive at a more adaptable public health response based on updated information“. And in fact, as we said, the most recent information on this aspect indicates a change in the typical symptomatology of Covid-19 patients.

The new symptoms

To photograph the change of course is the Zoe Covid Symptom Study app, an initiative launched last March to map i most common symptoms of Covid-19 and their evolution over the course of the disease, taking advantage of a free app and data (based on self-assessment) entered directly by users. Being a project born in the United Kingdom, the information it offers relates mainly to the English population, and given that at the moment in the country the variant delta is largely preponderant can be interpreted as one characterization of symptoms related to the new viral strain.

What does the latest data tell us? That for the unvaccinated and for those who have received only one dose of the vaccine (we are therefore talking about the patients who are most likely to contract the delta variant, for which, we have now learned, only two doses of the vaccine seem to provide reliable protection) , the first five symptoms most common are times of head, rhinorrhea (a runny nose), sore throat, sneezing e persistent cough. Extremely common symptoms, which could lead many people to underestimate the disease, perhaps mistaking Covid-19 for a trivial cold summer. Also because the loss of taste and smell, the signal that in the past was the most reliable indicator of a Sars-Cov-2 infection, no longer even enters the top 10.

The risk: underestimating the disease

Covid behaves differently lately, it looks more like a severe cold“, ha explained at Guardian Tim Spector, Professor of Genetic Epidemiology at King’s College London and coordinator of the Zoe Covid Symptom Study app project: “Many people may think they have just caught a seasonal cold, and keep going out of the house, going to parties… We think this phenomenon is fueling the problem. What is important to understand is that since the beginning of May looking at the most common symptoms reported by users of our app it is clear that they have changed from the past”.

Obviously, at the moment Spector’s are just hypotheses. The app is based on voluntary user reports and self-assessment of symptoms. And it clearly does not involve sequencing the virus to determine which viral variant has affected the individual patient. There delta variant it is currently largely prevalent, it is true, but there are other factors that could influence the symptoms of Covid-19 patients, such as vaccinations (in the UK 50% of the adult population is fully vaccinated, and nearly 80% have received at least the first dose) and the arrival of temperature summer (which encourage you to spend less time indoors).

In addition, despite the rising numbers of new cases, the country has not yet seen it soar to the top deaths e hospitalizations. And if on the one hand it may only be a matter of time, on the other it is also possible that the delta variant is proving to be very infectious, with a lethality due totransmission effectiveness, according to the WHO (and the new, milder symptoms could go in this direction). Or, perhaps even more realistic scenario, that vaccines and temperatures are taming the virus just enough to produce less severe symptoms, and therefore more similar to those of a normal cold. It is too early for certainties, in short, but in this period of calm one of the priorities is restore tracking, to cut down the circulation of the virus as much as possible, and therefore, given the data coming from the United Kingdom, even a simple runny nose could be a sufficient spy to choose to undergo a tampon.

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