Docs bank on clinical signs to differentiate between Omicron and Delta
Doctors said that a clinical differentiation between Omicron and Delta is crucial in terms of planning the treatment
Mumbai: Short incubation period, high fever lasting for fewer days, no lung involvement, no loss of smell or taste- these are some of the significant characteristics of the patients infected with the Omicron variant of the SARS-CoV-2.
However, in absence of quicker genome sequencing or the wide-scale unavailability of S-gene target failure tests used to indirectly detect Omicron, doctors have been using clinical signs to differentiate between the Omicron and Delta in order to decide the course of treatment.
Omicron is now the predominant variant in circulation in Mumbai. The latest round of genome sequencing carried out by the civic body has shown that nearly 88% of samples sent for sequencing had the Omicron variant, while the remaining were Delta (0.8%), Delta derivatives (8%) and other variants.
“There is very little Delta in circulation,” said infectious disease specialist Dr Vasant Nagvekar from the Lilavati Hospital. “We know this because a small number of patients have some lung infection, which is typical of Delta. But the majority of the cases are of Omicron which presents with an upper respiratory infection,” informed Nagvekar, who is also a member of Maharashtra’s Covid-19 task force.
Doctors said that a clinical differentiation between Omicron and Delta is crucial in terms of planning the treatment. Most importantly, it also helps in deciding if the patient should be considered a candidate for the expensive monoclonal antibody cocktail drug, as the cocktails currently available in India have failed to neutralise Omicron in a laboratory setting. The cocktail drug costs nearly ₹1.2 lakh and can be shared between two patients which brings the cost to around ₹60,000 each.
Nagvekar said that in Omicron when one family member develops the infection, others typically have it within three days.
“In Delta, this incubation period is about five to seven days. In Omicron, we typically see high fever, severe sore throat and headaches, but no changes in the chest scans, unlike Delta which speedily impacted the lungs,” he said, adding that when he suspects Omicron, he generally prefers waiting for 48 to 72 hours by administering only symptomatic treatment. “If I suspect Delta, I go ahead with Remdesvir or monoclonal antibody cocktails depending on the patient’s prognosis,” he said.
Dr Khusrav Bhajan, a physician and intensivist at the PD Hinduja Hospital said that the oropharyngeal or upper respiratory symptoms are the biggest indicators of Omicron. “Nearly 99% cases that we are seeing now are Omicron, but an occasional Delta has to be watched out for as it causes significant life-threatening problems.
Some of the city hospitals such as Lilavati and PD Hinduja are already in the process of procuring the Omisure kits that can detect Omicron within four hours.
“The kits will definitely be helpful when it comes to quickly detecting Omicron, and taking a call on whether the patient can be a candidate for a monoclonal antibody cocktail,” said internal medical specialist Dr Anita Mathew from Fortis Hospital in Mulund. “But we must remember that the cocktail is not a drug for the masses and must be used only for patients with the risk of progressing to severe disease,” she said.
Mathew added that most Covid-19 cases are self-limiting now. “This is not simply because we have Omicron in circulation, but also because the vaccine immunity is helping. When we suspect an Omicron, we prefer sitting tight and closely monitoring the patients, whereas, in Delta, we tend to quickly start an oral anti-viral or Remdesivir which comes in an injectable form,” she said.