As Covid-19 cases see a resurgence across India and the early monsoon ushers in a spike in flu infections, many are struggling to distinguish between the two. With overlapping symptoms like fever, sore throat, cough, body aches, and fatigue, it’s easy to misdiagnose or delay treatment. Dr. Suranjit Chatterjee, an internal medicine specialist at Indraprastha Apollo Hospitals in New Delhi, shares how to spot the differences and why testing is key to correct diagnosis and care.
The most challenging aspect, according to Dr. Chatterjee, is the clinical similarity. Both are respiratory viruses and can spread from person to person via droplets. However, the major difference lies in transmissibility and progression. Covid-19, especially in its recent mutated sub-variants, spreads faster and is more difficult for the immune system to detect early. Although the severity of symptoms in most current Covid-19 cases mirrors that of the Omicron wave generally mild complications can still arise, especially in vulnerable groups such as the elderly, immunocompromised, and individuals with co-morbidities.
One of the more distinct clinical differences between Covid-19 and flu is the effect on oxygen levels. While both viruses can cause pneumonia, Covid-19 leads to a more pronounced and quicker drop in oxygen saturation, sometimes across all age groups. This makes monitoring oxygen levels at home a critical step in early Covid-19 detection. Interestingly, some symptoms once thought exclusive to Covid-19 such as the loss of smell and taste have become less reliable indicators, especially with newer strains. These symptoms can also present in severe flu infections, further blurring the lines.
The timeline of symptom development also offers some clues. Flu symptoms typically appear one to four days after infection and resolve relatively quickly. In contrast, Covid-19 symptoms can take up to 14 days to appear and may last longer, sometimes leading to extended fatigue, inflammation, or what is commonly called long Covid. Another major difference is how long a person remains contagious. Those with the flu are usually infectious about a day before symptoms start and for several days afterward. Covid-19 patients, however, can begin spreading the virus even before symptoms show and remain contagious for up to a week or more. This longer infectious period makes Covid-19 a more potent super-spreader.
Testing remains crucial for identifying the virus. While flu can often be diagnosed clinically, if Covid-19 is prevalent in the community, an RT-PCR test is highly recommended. Early testing helps identify cases before they become severe and ensures the right protocols are followed to prevent further transmission.
Vaccination is another point of distinction. Annual flu vaccines are tailored to the latest circulating strains and are important to take, especially during monsoon months. On the other hand, current Covid-19 vaccines are based on older strains and may offer reduced protection against newer sub-variants. While infection-acquired immunity and past vaccine doses still offer some defense, the lack of updated vaccines remains a gap in protection.
In conclusion, while both illnesses demand attention, Covid-19 requires more proactive measures due to its wider spread, longer contagious period, and potential for severe respiratory complications. If you’re feeling unwell during this season, monitor your symptoms closely, check your oxygen levels, and don’t hesitate to get tested especially in high-risk zones. Vaccination against the flu remains vital, and staying informed is the best defense in a season where two similar viruses are circulating together.
