The threat lies in its easy transmissibility. The more numbers Omicron infects, the greater the spread. Even if a percent of the infected were to be hospitalised, the health system would collapse.
Omicron is less likely to infect the lungs and resides mainly in the upper airways. The heavily mutated virus is smashing daily case records, but hospitalisations and deaths are fewer compared to the peaks driven by Delta last year.
Even though cases are rising sharply — India reported almost 91,000 new cases on Thursday (previous 24 hours) compared to just 6,358 cases 10 days earlier — doctors across the country say almost all patients are coming in with mild symptoms: moderate fever, sore throat, headache, bodyache, and fatigue. Some patients have diarrhoea, nausea, and dizziness.
The US and the world reported a record 5.85 lakh and 18.95 lakh new infections on January 5. But the respective numbers of deaths that day were around 1,300 and 6,100 — down by about 3% and 9% from 14 days ago.
“The severity of disease with Omicron seems to be 66-80% less based on data from the UK and South Africa. South Africa’s experience also assures that a country like India that has already seen high levels of infections and has vaccination comparable to countries in the West with very little vaccine hesitancy, is likely to fare better,” said Dr Anurag Agrawal, an expert in lung disease and director of the CSIR-Institute of Genomics and Integrative Biology, New Delhi.
At AIIMS in New Delhi — where, Delhi Health Minister Satyendar Jain said on Monday, 81% of sequenced samples were of Omicron — no patient has developed pneumonia due to Covid-19, and none has needed oxygen or ventilator support solely for the coronavirus infection. Doctors have also reported that symptoms are resolving in about four to five days at most — much sooner than the average infection with Delta.
Dr G C Khilnani, a former head of pulmonology at AIIMS who is now the head of pulmonary, critical care, and sleep medicine at PSRI Hospital in New Delhi, said: “If the denominator gets big enough, then we will start seeing an increase in hospitalisation. It will target those who haven’t been vaccinated, those who haven’t had the infection, or those who have comorbidities in the community.”
Also, the highly infectious and immune-evasive variant is affecting doctors and healthcare staff — at least 120 doctors have tested positive in Delhi and are isolating or quarantining at four major hospitals. If cases continue to rise sharply for an extended period, more healthcare personnel will be infected, and hospitals could see staff shortages.
Omicron is at least 1.5-2 times more transmissible than Delta. It is also 2-3 times more capable than Delta of infecting those who have been fully vaccinated, or those who have had a previous infection.
“The risk of severe disease is less than Delta, but that is not saying much. I am not concerned about Delhi or Mumbai which have already seen huge Delta waves, and where health systems are fairly robust. The problem will be when Omicron spreads to places where the healthcare system is patchy, and there haven’t been Delta infections,” Dr Agrawal said.
“Also, in the initial phase of a wave, younger people who are out and about are more likely to catch the infection, but the disease is also less severe in them. We will understand the problem only when it starts affecting the old and vulnerable,” he added.
Dr Agrawal cautioned that while Omicron is “less likely to infect deep in the lungs, it still can.” And this distinction becomes more important as the denominator increases, he said. “Omicron is not a risk-free natural vaccine.”