Alpha, Delta, Omicron: With newer COVID variants, study reveals how symptoms continue to change

Unlike any other disease, COVID-19 has been highly unpredictable. With wide-ranging symptoms, long COVID complications and new emerging variants, SARs-CoV-2 virus has really impacted our lives in the most grievous ways.

Throughout the pandemic, we have tackled several new variants and mutations, either with strict measures or vaccinations. But with each new variant and subvariant, the symptoms have either gotten worse (Delta) or milder (Omicron).

Overall, according to a Zoe Health Study, there has been a considerable change in the type, length and severity of the symptoms, with each new variant of coronavirus.

Also read: Coronavirus: Study provides insight on who might be more likely to have long COVID

With the onset of the Omicron variant in November, 2021, the COVID symptoms have taken a milder turn, at least as compared to the Delta variant, which is said to have driven the second coronavirus wave in India.

Referring to their study, Zoe Health, in a press release, said that the people who contracted the Omicron variant were less likely to be hospitalized compared to those with the Delta variant.

Furthermore, the study revealed that the top symptoms of Omicron comprise a sore throat and a hoarse voice, in both vaccinated or unvaccinated individuals, which is not the case with the Delta.

Even with the emergence of new sub variants of Omicron in the recent past, although the cases have increased in certain parts of the world, due to its high transmissibility rate, there have been no severe cases lodged or reported, experts have said.

As compared to the Omicron, the Delta or the previous variants have always been more severe and life-threatening.

Even mild to moderate infection with Delta caused debilitating symptoms like fever, headaches, brain fog and eye soreness, whereas in severe COVID patients, symptoms like shortness of breath, chest pain, low blood oxygen levels were highly prevalent, with an increased risk of death.

With the help of the study, researchers also found a possible answer to why the Delta caused severe symptoms, while the Omicron still remains mild.

The Zoe Health Study involved participants, who tested positive between June 1 and November 27, 2021 (when the Delta variant was dominant) and between Dec. 20, 2021 to Jan. 17, 2022 (when the Omicron variant dominated).

Altogether, they collected 62,002 positive tests and analyzed the symptoms experienced by each participant.

Besides figuring out a difference in the length and types of symptoms between the two variants, the study also revealed that the Omicron is far less likely to impact the lower respiratory tract, which is where the virus seems to cause more damage and give light to severe symptoms.

In addition, the researchers also found that Omicron symptoms do not last as long in vaccinated people.

The respiratory system is classified into two main parts: Upper and lower respiratory systems.

The upper respiratory tract consists of the nose, nasal cavity and the pharynx, whereas the lower respiratory tract comprises larynx, trachea, bronchi and the lungs.

That said, an infection of the upper respiratory tract often includes the common cold, tonsillitis, a sinus infection, laryngitis and the flu, which cause mild symptoms such as a sore throat, runny nose, sneezing, headache, muscle pain, etc.

A lower respiratory tract infection on the other hand leads to illnesses such as bronchitis, pneumonia, bronchiolitis, tuberculosis and sometimes even the flu.

The SARs-COV-2 virus has also been identified to cause infections of both upper and lower respiratory tract, depending on the kind of COVID-19 variant one gets infected with.

While with the Delta, the infection of the lower respiratory tract was more prevalent, with Omicron, most people develop upper respiratory infection.

Experts believe the incubation period of Omicron, which is the period from being infected to experiencing the symptoms, is around three days, with the individual becoming infectious a day or two before symptoms emerge. This is said to be shorter than the incubation period for the Delta variant.

The average duration of illness with Omicron is also shorter as compared to illness with the Delta, which is five days compared to six.

According to the study authors of Zoe Health, Omicron symptoms last for shorter periods – an average of 6.87 days, compared to 8.89 days with Delta.

Irrespective of how COVID-19 or its symptoms have changed over the course of two years, the measures and the steps to protect oneself from the virus remain the same.

Wearing your mask, maintaining social distance, especially from those suffering from a common cold or flu-like symptoms, following proper hand hygiene is of utmost importance.

Additionally, those who are eligible for the vaccines should get their shots on time!

The manner in which the coronavirus infects a human body, the severity in which it affects the biological system and the long term adversities it puts a human body through is difficult to predict and sometimes it even gets difficult to diagnose.

It is therefore important to follow the anti-COVID protocols which include wearing masks, maintaining social distancing and keeping hands clean.

Apart from this individuals should also understand the COVID symptoms properly so that none of the symptoms are missed. This will give on-time medical assistance to the infected person and will also ensure that the virus does not spread among the ones who are in close contact with the infected person.