A new CDC study has shown that people who had tested positive for Covid-19 even one time had 1.5 times greater probability to have longer-lasting symptoms such as cough, headache, fatigue compared with people who had always tested negative for Covid-19. The findings of the study were published on September 10 in the latest Morbidity and Mortality Weekly Report.^1,2

A survey of about 6000 adults was conducted between January 2020 and April 2021 to find out persistence of symptoms associated with Covid-19 among those who had tested positive even once for Covid-19 or had always tested negative. Around 698 of those surveyed reported a positive SARS-CoV-2 test, while 2437 reported a negative test always; 2750 were never tested for SARS-CoV-2.

Results showed that nearly 66% of the participants who had tested positive even once for SARS-CoV-2 continued to have symptoms for more than a month compared to around 43% of the participants whose results were negative for SARS-CoV-2. They also reported more fatigue (22.5% vs 12.0%), change in sense of smell or taste (17.3% vs 1.7%), shortness of breath (15.5% vs 5.2%), cough (14.5% vs 4.9%) and headache (13.8% vs 9.9%).

Persistence of at least one symptom that had first appeared during the infection for more than 4 weeks was reported by 76.2% of people who had a positive test result compared to 69.6% of those whose test results were always negative.

About 28.7% of those who had tested positive believed that taking the Covid-19 vaccine had improved their symptoms compared to 15.7% of those who had always tested negative. No difference was found in reported beliefs that a vaccine made long-term symptoms worse.

This study reiterates that not just the acute disease, Covid-19 also leaves its impact as a long-term disease. Long-Covid or post-Covid is well-recognised now, though researchers are still unravelling its various facets, including why long-Covid occurs. It is now emerging as a public health issue of concern.

New long-covid symptoms are being identified almost every day. Early data on long Covid has largely come from patients who had been hospitalized with Covid-19. Long-Covid symptoms can develop in persons who did not require hospitalization, who also need long-term care just as the hospitalised patients. Everyone eligible must be encouraged to take the vaccine.

References

1. Even those who just test positive at more risk for long COVID: CDC - Medscape - Sep 09, 2021.
2. Wanga V, et al. Long-term symptoms among adults tested for SARS-CoV-2 - United States, January 2020-April 2021. MMWR Morb Mortal Wkly Rep. 2021 Sep 10;70(36):1235-1241. doi: 10.15585/mmwr.mm7036a1.