In coronavirus fight, an asymptomatic worry for Karnataka

The fight to contain the Covid-19 outbreak just got tougher, with a new finding alarming health authorities in the state.

Data from the state government showed that a significant chunk of new Covid-19 cases are ‘asymptomatic’ although they remain infected and highly contagious.

According to data from the Karnataka Covid-19 War Room, out of the 390 total Covid-19 cases reported in the state as of Sunday evening, 256 were asymptomatic.

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The largest numbers were within the Bruhat Bengaluru Mahanagara Palike (BBMP) limits, with 42 out of a total of 98 positive cases being asymptomatic, while in Mysuru, 54 out of total 83 cases belonged to the category.

The reason for the large rise in asymptomatic cases is because many of them have been identified early on, before they developed symptoms, said Dr Giridhar R Babu, a pandemic expert and a member of Karnataka’s Covid-19 Analysis Committee, which is tasked with identifying how the disease infects people and how to break the chain of the outbreak.

“Often, an infected person starts manifesting the severity of the disease in the second week. If somebody is tested in the first or early in the second week, they would generally not show any symptoms,” Dr Babu said.

However, he pointed out that the preliminary data also suggest that 2% to 5% of cases never show any symptoms throughout their period of infection such as fever, hacking cough, diarrhoea and the most telling symptom — shortness of breath.

In fact, two patients discharged in Bengaluru on Sunday, Patients 145 and 146 (husband and wife in their 60s), were asymptomatic for 14 days after their arrival in India from Dubai on March 22. They were eventually tested and found positive on April 5.

According to one patient who recovered from the Covid-19 at the Rajiv Gandhi Institute of Chest Disease (RGICD), Patients 2 and 3 were also asymptomatic throughout their isolation period at RGICD.

“Further studies are required to determine why some people do not show the symptoms of the disease as readily as others,” said Dr C Nagaraja, Director of RGICD.

Dr Babu pointed out all of these asymptomatic people were identified early by the government only because they happened to be first or secondary contacts of established Covid-19 individuals.

“If you extend that logic further, there may be many asymptomatics and symptomatic who don’t even come in contact with the health system at all but who are out there, part of the outbreak,” he said, adding that only a comprehensive syndrome-based approach with enhanced testing would catch all the unknown cases out there.

In almost every instance, according to data analysed by DH, every identified positive case, who is also a contact, falls into three categories: family members, friends or co-workers. There are almost no identified cases falling outside these categories.