Coronavirus: If you had the original Omicron infection, can you still catch 'stealth' Omicron?

Although COVID-19 cases have dropped in several parts of the world, experts believe the next surge is just around the corner. The World Health Organization (WHO) in a recent press interview told reporters that the sudden rise in coronavirus cases worldwide is just the "tip of the iceberg". China, South Korea, Hong Kong and some parts of Europe are currently grappling with an uptick in the COVID-19 cases and one of the reasons has been attributed to the 'Stealth' or the BA.2 subvariant of the Omicron variant.

Also read: Coronavirus: Reasons why COVID-19 cases are rising around the world, as per the WHO

The BA.2 or Stealth Omicron is a sub-lineage of COVID's Omicron variant. Just like its parent strain, the WHO says that it also affects the upper respiratory tract and causes mild infections. Preliminary research reveals that it can also evade and dodge vaccine-induced immunity, leading to breakthrough infection. However, one factor that separates the Stealth Omicron to its original strain is its ability to escape detection.

As per experts at the U.K. Health Security Agency (UKHSA), the BA.2 subvariant is missing key mutations in the spike protein, which is integral to the detecting process. COVID's Omicron variant contains a genetic deletion in the “S” gene that makes it more detectable. However, in the Stealth Omicron, there is no S gene drop out, which makes it harder to track.

Additionally, a Danish study also found that BA.2 is substantially more transmissible than the BA.1 sub-variant. In a recent update, the WHO said that the highly transmissible subvariant may be driving the current surge in coronavirus cases globally.

During the Omicron wave, many people came down with cold-like mild symptoms including sore 'scratchy' throat, runny nose, fatigue, body pain, mild fever and cough. Now, the widespread surge of Stealth Omicron infection has people confused and left them wondering as to whether they are prone to a reinfection.

According to a recent study by Denmark's Statens Serum Institut, if you've had an Omicron infection in the past, you're unlikely to catch the BA.2 subvariant or get infected twice. But the researchers also state that it could be possible in certain cases.

Also read: Turn your body into a 'fat-burning machine': Dr Michael Mosley's sensational remedy to lose weight

The study found that out of more than 1.8 million COVID-19 cases, recorded between November 21 and February 11, only 1,739 patients tested positive twice between 20 and 60 days apart.

It was found that the re-infections occurred mostly in young and unvaccinated individuals, with very mild symptoms, reported Hartford HealthCare.

Out of the 1,739 patients who were reinfected, 47 people had the stealth Omicron after an infection from the original strain.

Experts and epidemiologists have said that a reinfection is "very unlikely" but still possible.

Dr Allison Arwady, Chicago Department of Public Health Commissioner, says that people who have had the Omicron infection are not likely to catch it twice, at least not within three months.

However, Stanley Weiss, an epidemiologist at Rutgers School of Public Health, in conversation with Yahoo, said, "Yes, you can get Omicron twice."

"If you had a mild infection, didn’t get a very good immune response, and you get exposed again with a big dose of the virus, it’s definitely possible."

An Israeli study also found cases of reinfection with stealth Omicron after getting infected with the original strain.

Cyrille Cohen, head of the immunotherapy lab at Israel’s Bar-Ilan University, said, "We [have] received some…reports that in very rare occurrences so far, people that…were infected with Omicron could also…be infected with BA.2," as reported by i24 news station.

Experts believe there is no significant difference between symptoms of Omicron and it's subvariant.

As per UK's ZOE symptoms study App, here are some of the symptoms reported in people with Omicron infection.

- Runny nose

- Scratchy throat

- Headache

- Fatigue

- Sneezing

- Body pain

- Night sweats

- Loss of appetite

- Vomiting

Following COVID-appropriate behaviour, which includes wearing masks, maintaining distance and washing hands frequently is key to curbing the spread of the virus. Vaccinations are integral to tackling the COVID-19 crisis and those who are eligible for booster shots must get it immediately.