All about XBB.1.16, new Omicron variant behind India's Covid-19 spike, from symptoms to risk factors
India has witnessed 40% jump in daily Covid-19 cases. All you want to know about XBB.1.16, the new Omicron variant responsible for the spike.
XBB.1.16, the new Omicron variant that is leading to rise in number of Covid-19 cases across the country, especially in Maharashtra has become a cause of concern for people. XBB.1.16, first detected in Pune in February this year is said to be fast replacing the dominant strains in the country. Named officially as XBB.1.16 on March 5, the sub-variant rapidly transmits and has additional mutations in its nucleotide and amino acids. The hybrid lineage of recombinant XBB, this strain that first emerged in 2021 is resulting in high transmission rate. A mutant strain of Omicron, it can elude hybrid immunity and of that gained by vaccination. Meanwhile, India has seen over 40% jump in daily Covid-19 cases - highest since six months - which seems to be driven by the new variant. (Also read: XBB.1.16 driving fresh Covid-19 spike in Maha, dominant strain in Pune)
What is XBB 1.16
"The XBB 1.16 subvariant is a highly transmissible variant with high infectivity rate. The subvariant has mutations on the amino acids and nucleotide space that gives it the capacity to escape hybrid immunity achieved by vaccination and previous exposure to the virus," says Dr Charu Dutt Arora, Infectious Disease Specialist, Consultant Physician, AmeriHealth, Asian Hospital.
What makes XBB.1.16 risky
"Due to its high contagiousness and rapid spread, this new variant is being viewed as a danger. XBB.1.16 is a hybrid lineage of the virus and is descended from the XBB lineage of Covid-19. This allows the mutant SARS CoV 2 strain, primarily of Omicron, in XBB.1.16 to deftly evade the immune system. Since it first appeared in late 2021, the Omicron variety has gained a reputation for having a high transmission rate. XBB variants that are currently in circulation globally. XBB is a hybrid of two Omicron sub-variants, as you are aware. The capacity to overcome immunity from prior infections and vaccinations is very strong in all Omicron sub-variants. More mutations occur as a means of evading immunity as strain increases," says Dr Anurag Saxena, HOD- Internal Medicine, Primus Super Speciality Hospital, New Delhi.
"Cellular immunity still affects the variations, though. In samples from five states—four of which are experiencing a rise in COVID-19 cases—the new variant of interest XBB.1.16 has been found. The Sars-CoV-2 genome sequencing collaboration in India, INSACOG, has discovered at least 344 XBB.1.16 sequences. According to a search of the worldwide database GISAID, 49% of the XBB.1.16 sequences that have been submitted to it so far are from India. Although it has been replacing other dominant variants, this more transmissible one is unlikely to result in a large number of instances," he adds.
Symptoms of XBB.1.16
Dr Arora says the signs and symptoms of the new sub-variant are almost the same as that of Omicron variant.
"High grade fever for more than 48 hours, cough, sore throat, body pain, severe headache, cold and abdominal discomfort. There is no loss of smell or taste seen in the patients, so far. Most of them have mild to moderate disease and are being managed on home isolation," says Dr Arora.
"The XBB.1.16 version does not appear to be seriously harming people right now. Upper respiratory symptoms like a blocked nose, headache, sore throat, fever, and myalgia, or muscular discomfort that lasts for three to four days, are typical," says Dr Saxena.
"The symptoms of this new variant are mostly low-grade flu-like. People may experience symptoms in the upper and lower respiratory tract. In terms of upper respiratory tract symptoms, people may experience nasal discharge, a sore throat, a slow-rising fever that lasts for one or two days, and loss of smell. In case of these symptoms, it is recommended to get tested for COVID. For lower respiratory tract symptoms, people may suffer from severe bronchitis and cough," says Dr Kuldeep Grover, Head of Critical Care & Pulmonology, CK Birla Hospital (R), Gurugram.
How XBB.1.16 different from other Omicron sub-variants
"While there may be a slight rise in cases, a large wave like the one that occurred in January 2022 when Omicron first entered India is unlikely to result. It might resemble the smaller increases that were noted later that year, around April, when the Omicron sub-variants BA.4 and BA.5 were recorded. Without immunization, I believe that almost all of us contracted the Omicron wave of 2022 after contracting the Delta wave of 2021. Two variants have been subjected to by the majority of Indians, and they are still keeping us safe from serious illness," says Dr Saxena.
Who are at risk population?
Dr Arora says patients with co-morbidities such as elderly population, or with cardiac conditions, previous pulmonary issues such as asthma, tuberculosis, diabetic and chronic kidney disease patients are at high-risk for catching infection.
“This new variant is different from others in the sense that it spreads faster than other variants. However, hospitalization rates are very low and can be managed at home. In recent times, people who have been vaccinated and exposed to natural infection during the last COVID waves are developing strong immunity against the virus, which is called hybrid immunity. In hybrid immunity, the body develops antibodies that help fight against mutations of the virus. It has been seen that COVID cases are rising, but they will not lead to massive hospitalizations because of hybrid immunity,” says Dr Grover.
Is there any need to worry?
"There is no need to panic. We have had a successful mass vaccination program and been exposed to this virus multiple times. However, one must continue to follow the Covid appropriate behaviour such as hand hygiene and masking. High risk population should be more vigilant and take more precautions. One must isolate themselves if has any travel history or symptoms of the disease and see the physician at the earliest to avoid any complications," says Dr Arora.
How we can avoid this health scare
Dr Saxena says an additional booster dose apart from Covid-appropriate precautions can help curb the spike. He also feels people who are comorbid should take additional precautions.
"We must continue living our lives, after all. However, people can take some precautions to reduce exposure, particularly the elderly, those who are comorbid, and those who are at high risk for serious illness. For instance, going to the movies is not essential and those at high risk can avoid it when the infection is in circulation. Instead, they should avoid congested, poorly ventilated spaces. When they are in a crowded vehicle, metro, or airplane, they can wear mask. Those who have not received their vaccinations can do so. The only effective tactic is that one," says the expert.
"India has a poor coverage rate for booster doses, at just 27%. Should individuals receive a final chance? The majority of people have finished their primary vaccination, and since we have already been exposed to the infection, an extra dose of the same vaccine will only marginally improve our level of protection. Cost-benefit analysis reveals a low number. If you are qualified, you can receive the injection. Precautions like hand washing, respiratory hygiene, proper ventilation in homes and workplaces, and masking up in crowded places are more crucial. These precautions will shield individuals from the flu and other contagious viruses," concludes Dr Saxena.