Symptoms for early COVID-19 infection differ among age groups and between men and women, according to new research. These differences are most notable between younger age groups (16 to 59 years) compared to older age groups (60 to 80 years and older). Researchers also found that men have different symptoms compared to women in the early stages of COVID-19 infection.

Investigators at King’s College London analyzed data from the ZOE COVID Symptom Study app between April 20 and Oct. 15, 2020. App contributors are invited to get tested as soon as they report any new symptoms. The researchers modeled the early signs of COVID-19 infection and successfully detected 80% of cases when using three days of self-reported symptoms.

The team compared the ability to predict early signs of COVID-19 infection using current National Health Service UK diagnostic criteria and a Hierarchical Gaussian Process model, a type of machine learning. This machine learning model was able to incorporate some characteristics about the person affected, such as age, sex, and health conditions. This investigation revealed that symptoms of early COVID-19 infection are different among various groups.

The study analyzed 18 symptoms, which had different relevance for early detection in different groups. The most important symptoms for earliest detection of COVID-19 overall included loss of smell, chest pain, persistent cough, abdominal pain, blisters on the feet, eye soreness and unusual muscle pain. However, loss of smell lost significance in people over 60 years of age and was not relevant for individuals over 80. Other early symptoms such as diarrhea were key in older age groups (60 to 79 and 80 and older). Fever, while a known symptom of disease, was not an early feature of the disease in any age group.

Men were more likely to report shortness of breath, fatigue, chills and shivers, whereas women were more likely to report loss of smell, chest pain and a persistent cough. While these models were generated in the COVID Symptom study app, models were replicated across time suggesting they would also apply to non-app contributors.

Although the models were used on the first strain of the virus and Alpha variants, the key findings suggest the symptoms of the Delta variant and subsequent variants will also differ across population groups.

“It’s important people know the earliest symptoms are wide-ranging and may look different for each member of a family or household,” said lead study author Claire Steves who is with King’s College London, England. “Testing guidance could be updated to enable cases to be picked up earlier, especially in the face of new variants which are highly transmissible,”

Flu shots may offer some protection against COVID-19

The flu vaccine may provide vital protection against COVID-19. A new study that included 74,754 individuals analyzed patient records from around the world and found that the annual flu shot reduces the risks of stroke, sepsis, and DVT (deep vein thrombosis) in patients with COVID-19. Patients with COVID-19 who had been vaccinated against the flu were also significantly less likely to visit the emergency department and to be admitted to the intensive care unit.

“Only a small fraction of the world has been fully vaccinated against COVID-19 to date, and with all the devastation that has occurred due to the pandemic, the global community still needs to find solutions to reduce morbidity and mortality,” said senior study author Dr. Devinder Singh, who is chief of plastic surgery and a professor of clinical surgery at the University of Miami Miller School of Medicine in Florida.

Having access to the real-time data on millions of patients is an incredibly powerful research tool, added Dr. Singh. The study was conducted using patient records from a number of countries, including the U.S., the U.K., Germany, Italy, Israel and Singapore.

The analysis revealed that those who had not had the flu shot were up to 20% more likely to have been admitted to the ICU. The unvaccinated were up to 58% or more likely to visit the emergency department, and up to 45% or more were likely to develop sepsis. The findings were similar for stroke (up to 58% more likely) and a DVT (up to 40% more likely). The risk of death was not reduced.

Although it isn’t exactly known yet how the flu vaccine provides protection against COVID-19, most theories speculate that the flu shot may boost the immune system. The results strongly suggest that the flu vaccine may protect against several severe effects of COVID-19. However, the authors write that more research is needed to prove and better understand the possible link between the flu vaccine and COVID-19 complications. The authors contend that continued promotion of the influenza vaccine also has the potential help the global population avoid a possible ‘twindemic’ (a simultaneous outbreak of both influenza and coronavirus).

Giving grandkids a breath test before they visit

Adults infected with the COVID-19 virus exhale different metabolites in their breath than uninfected people, and dogs and diagnostic devices can detect these changes. Now, researchers have shown that children infected with the virus also show breath metabolite changes, but they’re largely different from the ones in adults.

These new findings are very promising and suggest that kids as well as adults may be able to avoid exposure to COVID-19 with a simple breath test. Currently, COVID-19 is diagnosed through the detection of specific viral nucleic acids or antigens, but these techniques are slow, relatively expensive, sometimes uncomfortable, and prone to false-negative results.

Scientists have observed that dogs can detect volatile organic compounds (VOCs) in human biological samples and distinguish certain diseases, including COVID-19. Researchers have also developed a sensor array to detect COVID-19-related VOCs in the exhaled breath of adults. It is hoped these advances can help to slow the spread of the disease.

John Schieszer is an award-winning national journalist and radio and podcast broadcaster of The Medical Minute. He can be reached at medicalminutes@gmail.com.