Coronavirus: How to know if you have caught Omicron or a Delta infection?

Time and again, coronavirus variants have emerged and wreaked more havoc than expected. While COVID's Delta variant was one of the sole reasons behind the second wave in India, it is believed that the new and the latest strain, Omicron, may drive a possible 3rd wave in the country. The rising number of COVID-19 cases are evidence enough to prove the same.

Both Delta and the Omicron are 'variants of concern'. Comparatively however, the former is more severe than the latter. Up until now, experts and doctors have found that the new COVID variant causes mild symptoms, which was not the case with the Delta.

Having said that, with many testing positive for the SARs-COV-2 virus, there is an increasing curiosity among people to know whether what they have is an Omicron infection or the Delta.

Read also: Coronavirus: Will my rapid antigen test or RT-PCR tell me if I have Omicron?

As opposed to the Delta variant, Omicron infections have been considerably milder, but more infectious. According to a study by a Japanese scientist and a professor of health and environmental sciences at Kyoto University, Hiroshi Nishiura, the transmissibility rate is 4.2 times higher in the Omicron variant as compared to the Delta.

“The Omicron variant transmits more, and escapes immunity built naturally and through vaccines more," he says.

In another French study, published on the medRxiv site, it was found that COVID's Omicron variant may be 105% more transmissible than Delta.

So far, the available data only proves that the new variant is highly transmissible and can infect a large population in a short span of time, which it has done successfully in the recent past.

Since the onset of the Omicron variant, scientists have been closely monitoring the new strain. Apart from the heavy mutations in the variant's spike protein, doctors have also found some changes in the symptoms.

Read also: Coronavirus: 3 Omicron symptoms that need to be taken into account immediately

Initially, when the Omicron variant was first detected in South Africa, Dr Angelique Coetzee, Chairperson of the South African Medical Association said that the disease was mild and people who were infected did not report any severe symptoms. As per Dr Coetzee, individuals infected with the Omicron complained of "scratchy" throat and mild body temperature that gets better on its own.

Comparing the Omicron variant with the Delta, Dr. S.N Aravinda, Consultant - Internal Medicine, Aster RV Hospital, JP Nagar, Bengaluru says that the effects of COVID-19 variants may differ from person to person.

"Some reports suggest that people with Omicron are less likely to lose their sense of smell, which has been noticed with other variants. Delta may result in more severe symptoms if critical whereas Omicron so far has milder symptoms and typically the lung involvement is lesser and patients do not require oxygen," he elaborates.

Adding further, the doctor suggests that Omicron may not cause breathlessness as it largely multiplies in the throat. However, he believes that it will take more research and a deeper understanding to clearly know the difference in the symptoms.

When it comes to COVID-19, both antigen and molecular tests help identify the presence of SARs-COV-2 virus in the body, irrespective of which variant you have. While a molecular test, also known as PCR (Polymerase Chain Reaction ) testing takes more time to provide the results, a rapid antigen test reveals the COVID status in a very short span of time.

Currently, RT-PCR and rapid antigen tests are used to determine if a person is COVID positive or negative, says Dr. Aravinda. However, to check if it is the Omicron variant then gene sequencing is the step ahead, he adds.

That said, to confirm whether a suspected case is Omicron requires a full genetic analysis, which can take between four and five days. With the help of the genetic material provided though testing, scientists can confirm if someone is infected with the Omicron or the Delta.

"Omicron and Delta are both different variants of coronavirus. If we want to know which variant is infecting us then it has to be at the genome level," says Dr Ankita Baidya, Consultant - Infectious Disease, Manipal Hospital, Dwarka.

As per the infectious disease expert, "Genome sequencing is where viral genome and the genetic structure of the viral organism is sequenced after performing the PCR, based on which it is determined whether it is an omicron or delta variant."

After a PCR test is conducted, the tests look for three genes in association with different parts of the virus which are spike (S), nucleocapsid or inner area (N2) or outer shell (E).

According to Dr Baidya, "If the S gene PCR comes out as positive, then the chances are that it is not an Omicron infection, but the currently circulating Delta infection." However, the doctor also says that if the S gene PCR is negative, it does not necessarily indicate the presence of Omicron or any other variant.

In order to eliminate delays in genome sequencing to detect the Omicron variant, the Indian Council of Medical Research (ICMR) has approved an RT-PCR test kit, known as "Omisure", developed by Tata Medical and Diagnostics, to specifically identify the new variant.

The cost of the Omisure test kit is fixed at Rs 250 per test, but since it is not an at-home testing kit, additional costs may pertain to it.