ICMR study on long Covid: What its key findings say on post-Covid-19 conditions, vaccine efficacy

The study is based on the data of 14,419 patients across 31 hospitals. It includes patients who were hospitalised since September 2020, meaning the infections are likely to have been caused by the original, delta, or omicron coronavirus variants. Besides, it looks at outcomes only in those who were hospitalised with moderate to severe disease.

Apart from the findings mentioned above, the study found that 17.1% of the participants experienced post-Covid-19 conditions such as lethargy and breathlessness, and cognitive abnormalities like brain fog and difficulty in concentrating. It also said that people were nearly three times more likely to die if they experienced these post-Covid-19 conditions.

The study put in a caveat that the exact definition of “post-Covid-19 conditions”, as given by World Health Organization or Centers for Disease Control and Prevention (CDC) could not be used, as they came out after patient enrolment had already begun. The ICMR study defines “post Covid-19 conditions” as persistent or new onset of fatigue, breathlessness, or cognitive abnormalities.

The study also showed that even a single dose of the vaccine before the infection reduced the number of deaths in the one-year period by 60%.

Who was at higher risk of mortality?

The factors that increased the risk of death later in the year following a Covid-19 infection were comorbidity, age, and gender. The study found that people with one comorbid condition were more than 9 times likely to die during the year following the infection. Men were 1.3 times more likely to die and those above the age of 60 years 2.6 times more likely to die, according to the data.

Children between the ages of 0 and 18 years were at a 5.6 times higher risk of death between the first follow-up at four weeks and the follow-up at one-year mark. This risk was 1.7-fold in the four weeks immediately after hospitalisation, meaning more children died later in the year.

“Our earlier reports have shown that comorbidities among admitted children are more severe, such as malignancies, kidney disorders, haematological disorders and others. This could be hypothesised as one of the reasons for the higher odds of death among these children,” the study said.

With comorbidity increasing the likelihood of death the most, a former scientist from ICMR previously associated with the study, said: “This clearly shows that comorbidities are an important risk factor. So, people with any comorbidities, especially conditions such as liver cirrhosis and chronic kidney disease, must take all precautions because they are likely to get severe disease and complications. They must stay in touch with their doctors and monitor their conditions well.”

Could people infected with the milder variants also get long Covid?

Dr Suranjit Chaterjee, senior consultant of internal medicine at Indraprastha Apollo hospital, New Delhi, who is not associated with the study, said: “From the evidence so far, long Covid may happen even in people who have had bouts of mild Covid-19. The symptoms improve with therapy and pills.”

However, he said, long Covid-19 was perhaps being over-diagnosed. “Any symptom for which a cause cannot be determined is being attributed to a previous Covid-19 infection. There is a need to look at alternative causes for any symptoms reported by patients, and to specify exactly what should be considered long Covid-19 and what not.”

Should those at risk of severe disease take precaution doses?

Dr Chaterjee said that at the moment there was no need to take additional doses of the vaccine as the disease remains mild — just upper respiratory symptoms such as cough and cold — in most people.