New Delhi: Is the omicron variant mild? Does it cause a less deadly disease? A negative answer to the first question doesn’t necessarily mean a negative answer to the second one as well. This is because they are about different aspects of epidemiology.
But in response to a question at a press conference on March 3, Union health ministry joint secretary Lav Agarwal mixed them up.
The context was that India’s third wave, driven by the spread of the omicron variant, was not nearly as devastating as its second wave. Agarwal attributed this fact entirely to India’s successful response to and management of the disease.
When a reporter contended that the omicron variant is less lethal, implying that the government couldn’t take all the credit, Agarwal demurred.
Agarwal’s opinion was in line with a similar claim by his colleagues in India’s COVID response team, co-secretary Rajesh Bhushan, NITI Aayog member and vaccination drive chief Vinod K. Paul, and Indian Council of Medical Research director-general Balram Bhargava.
At the time, these officials had lauded India’s COVID-19 vaccination drive for reducing the number of deaths in early 2022 versus in early 2021.
In both instances, on January 20 and March 3, the principal difference between the intensity of the two waves was that the omicron variant is less able to kill than the delta variant.
Explanation
The omicron variant is more transmissible than the delta variant. In other words, it spreads faster than the delta variant. Therefore, the overall case trajectory is very high. In this sense, the omicron variant is not mild.
The omicron variant causes less severe infection than its ‘predecessor’, the delta variant. So it is also less lethal (i.e. able to cause death) as a result. The WHO as well as independent studies have said as much. A technical brief the WHO published on January 21, 2022, said the following:
“Epidemiological trends continue to show a decoupling between incident cases, hospital admissions and deaths, compared to epidemic waves due to previous variants. …
This is likely due to a combination of the lower intrinsic severity of Omicron, as suggested by a number of studies from different settings, and that vaccine effectiveness is more preserved against severe disease than against infection.”
Researchers have reasoned this is because the omicron variant is not as effectively able to damage the lungs as the delta variant can, among other possibilities. Ravindra Gupta, a virologist at the University of Cambridge, also told Nature News that the omicron variant has difficulty entering the lungs.
One of the earliest studies to this end was conducted in South Africa. Its paper clearly indicated “lower odds” of a severe disease in patients infected with the omicron variant versus the delta variant.
Agarwal referred to the ongoing surge of cases in the Western Pacific region. Hong Kong in particular is going through its worst phase of the pandemic. However, this is not related to whether the omicron variant causes severe disease.
In fact, the January 21 WHO technical brief had said that a higher level of transmission could result in more cases – which in turn could result in more hospital admissions.
So, there is no denying that India’s third wave was less debilitating for the country than the second wave. This was partly due to vaccination coverage – and partly because, contrary to Agarwal’s claim, the omicron variant is less lethal than the delta variant.