Wily coronavirus leaves docs clueless on recovery rates

As COVID-19 continues its romp across the state, an analysis of recovery patterns of affected cases reveals that the disease affects different people in different ways and that this often has nothing to do with how old or physically fit one may be.

An analysis of all patient data made available by the state health department during Karnataka's official, 35-day outbreak so far has revealed a surprisingly fluctuating picture of recovery rates.

Nothing seems to be relevant to predict a patient's recovery — not age, not immunity, not even co-morbidity factors. The only factor that seems to matter is how high a patient's viral load is, a senior medical official said, adding that the cause of high viral load is itself a mystery.

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In some instances, elderly or middle-aged patients have made spectacularly quick recoveries, even as young adults in the prime of life have taken upwards of 20 days to recover. "This shows that a great extent of the knowledge about this disease is still absent,” state medical officials said.

In some cases, patients appear to make progress for the first four days, before they crash in a "cytokine" storm where massive virus replication in the body causes the immune system itself to attack the body, according to molecular biologist Dr Deepak Saini, a member of the state's COVID-19 Coordination Committee. "This can prove fatal," Dr Saini said.

The unpredictable nature of recovery from COVID-19 is best highlighted by the case of Patient 75, a healthy, 26-year-old man who made the fastest recovery in the state so far, requiring just nine days before the virus passed from his system. On the other hand, an equally healthy 31-year-old man (Patient 19) made one of the slowest recoveries to date — taking 25 days. Patient 19 was discharged from the Rajiv Gandhi Institute of Chest Diseases (RGICD) on Tuesday.

Although the death toll in the state is largely skewed to those over the age of 55, a 67-year-old woman and a 70-year-old man also survived the disease and were discharged within the normal, 14-day period of isolation.

According to Dr C Nagaraja, Director of RGICD, the hospital’s own experience showed that three out of the nine discharged patients (including Patient 19) had an unusually delayed recovery.

“Patient 19’s case is important. Although his mother, Patient 22 (64 years), was discharged after 21 days in isolation, he himself was taking a lot of time to discharge the virus even though his immune system was normal and healthy,” Dr Nagaraja said.

“We are not exactly sure why. It is also unknown why Patient 3 (a 13-year-old) was not able to get cured quickly, even though her mother, Patient 2, who is 47 years, cleared the virus from her body in 14 days,” he added.

“There appears to be no clear methodology to determine the recovery rate of patients. The only thing that we can think of at the moment is a high viral load, but what causes high viral loads in people is still unknown,” Dr Nagaraja said.

More studies needed

According to Dr Saini, people primarily die of COVID-19 if they are not able to reduce the viral load in their bodies, which results in secondary infections like Severe Acute Respiratory Infection (SARI).

Dr Saini said he suspects weakened immunity and co-morbidity play a factor, but said further studies were required. “If you have an immune system that is partly compromised, you will presumably take a longer time to clear away the infection,” he said.

Men more vulnerable

Although the data analysis is limited to recovery and fatality statistics, the figures appear to indicate that men are at more risk of COVID-19 than women. Of the 65 people discharged after being cured so far in the state, 46 are men, plus one male baby, and 18 are women. Out of those still under prolonged isolation (over 15 days), the numbers even out somewhat with 14 men and nine women. Among fatalities disclosed so far, seven are men and two are women.