Coronavirus explainer: Study reveals which COVID variant is more likely to cause long COVID

The SARs-CoV-2 virus, like any other virus, is programmed to mutate. Over the course of the pandemic, several new variants of COVID-19 have emerged, displaying new and unusual symptoms of its own. While some variants like the Delta have proved highly dangerous, strains like the Omicron have been milder and more manageable.

With new variants, the possibility of long COVID, which refers to long term coronavirus symptoms that linger on weeks and months after recovery, has been explored widely.

A recent study conducted by a team of researchers from the United Kingdom looked into the possibility of long term COVID symptoms with the Delta and the Omicron variant and the results are likely to surprise you!

Also read: Coronavirus effect: Signs and symptoms of long COVID, as per research studies

A group of researchers from King's College London have found the odds of developing long COVID after infection are 20 to 50 percent lower during the Omicron wave in the UK compared to the Delta.

The peer reviewed study, published in the medical journal Lancet, used data from the ZOE COVID Symptom study app.

It involved 56,003 UK adults who were infected between Dec 20, 2021, and March 9, 2022. These cases are hereafter referred to as omicron cases as more than 70% of UK cases were estimated to be attributable to the omicron variant during that time, as per the study.

The study also looked into 41,361 patients who first tested positive between June 1, 2021, and Nov 27, 2021, when over 70 percent of the cases were that of Delta.

The research included both symptomatic and asymptomatic infections for the Delta period, while for the Omicron period, only participants testing positive before Feb 10, 2022 were considered. This was to make sure that all the participants had at least 28 days for symptom reporting after testing positive.

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The study found: Among omicron cases, 2501 (4·5%) of 56 003 people experienced long COVID and, among delta cases, 4469 (10·8%) of 41 361 people experienced long COVID. Omicron cases were less likely to experience long COVID for all vaccine timings, with an odds ratio ranging from 0·24 (0·20–0·32) to 0·50 (0·43–0·59). These results were also confirmed when the analysis was stratified by age group.

"It's good news, but please don't decommission any of your long COVID services," lead researcher Dr Claire Steves told Reuters.

Both the Delta and the Omicron variant are strains of the SARs-CoV-2 virus. While the two are the by-products of the same virus, experts have noticed certain differences in the two.

While both the variants are highly transmissible and infectious, the Delta variant is said to be more severe than the Omicron.

During the second coronavirus wave in India, the range of symptoms experienced with the Delta were more wide-ranging and serious. From mild to moderate symptoms such as fever, cough and fatigue to severe symptoms including shortness of breath, chest pain and low oxygen levels, many required medical intervention, while many others succumbed to the virus.

However, the Omicron wave was more merciful as compared to the Delta. While a large population of people were infected, the symptoms do not go beyond sore throat, runny nose, cough, fatigue and muscle pain. In most severe cases, people experienced gastrointestinal issues.

Some people who have been infected with the virus that causes COVID-19 can experience long-term effects from their infection, known as post-COVID conditions (PCC) or long COVID, says the US Centers for Disease Control and Prevention (CDC).

As per the health agency, some of the symptoms include:

- Tiredness or fatigue that interferes with daily life

- Symptoms that get worse after physical or mental effort (also known as “post-exertional malaise”)

- Fever

- Difficulty breathing or shortness of breath

- Cough

- Chest pain

- Fast-beating or pounding heart (also known as heart palpitations)

- Headache and dizziness

- Brain fog

- Pins and needles

- Joint and muscles pain