When will I know that I have Corona? This question cannot be answered unequivocally, as more and more infections are asymptomatic. A new study has now revealed that if symptoms do appear, they will appear much earlier than when the pandemic began.
Sneezing, runny nose, fever, cough and loss of smell and taste are the most well-known first corona symptoms. However, you can become infected with Corona and remain completely symptom-free. With the omicron variant, experts assume that more than half of the people infected with corona do not even notice it. FITBOOK reported about it. In a large study analysis, Chinese scientists have now found that the first corona symptoms appear earlier with each virus mutation. This could have consequences for the period of self-isolation.
Incubation period decreased from 5 to 3.5 days
Chinese scientists from Beijing University have evaluated data from 142 different corona studies and found that since the beginning of the pandemic two and a half years ago, the incubation period of the corona virus has decreased with each new variant.1 This means that the first corona symptoms are currently occurring in many infected people earlier than two years ago. The average incubation period for the alpha variant, which first appeared in Wuhan, China, at the end of 2019 was five days. In contrast, the incubation period of the currently most widespread omicron variant is on average 3.5 days, according to the researchers.
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Corona symptoms of 8112 infected people evaluated
The researchers evaluated data on the incubation times of a total of 8112 corona patients. Although the symptoms can appear at different times in each person, a clear trend can be seen as the pandemic progresses: «The results of this study indicate that SARS-CoV-2 is continuously evolving during the Covid 19 pandemic and has mutated,” study leader Min Liu is quoted as saying by the science portal “Medical Xpress”. The virus has not only changed in terms of transmissibility and severity, but also in terms of the incubation period. According to the study, the incubation period, i.e. the period from the time of infection with the virus until the onset of the disease with the appearance of the first corona symptoms, is as follows:
- Alpha variant: 5 days
- Beta variant: 4.5 days
- Delta variant: 4.4 days
- Omicron variant: 3.4 days
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In their analysis, the researchers note that at the beginning of the pandemic, the coronavirus had an unusually long incubation period of five days. For example, cold viruses have an incubation period of 3.2 days. Flu viruses even less than two days. However, it should be noted that the study results are average values. There were corona patients who gave completely different results: the shortest reported incubation was 1.8 days, the longest 18.87 days.
Findings could result in a shorter quarantine
The data suggest that, at least with the omicron variant, the time until the first corona symptoms appear has been significantly reduced. This also shortens the period in which corona patients are contagious to others. «Currently, some countries require that close contacts be prevented for 14 days,» the scientists write in their study evaluation. «With the shortening of the incubation period of the new variants, however, the isolation period can be adjusted accordingly to reduce the pressure on the healthcare system,» the researchers recommend. In Germany, the recommendation for quarantine or isolation is only five days.2
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At the latest when the following corona symptoms appear, a rapid test should be carried out to detect an illness and to protect others from infection:
- Fever
- Cough
- fatigue
- Loss of smell and taste
- shortness of breath
- tiredness or exhaustion
- body aches
- headache
- Sore throat
- Stuffy or runny nose
- loss of appetite
- Diarrhea
- nausea
- Night sweats accompanied by intense, vivid dreams