DNA Explainer: How new COVID-19 variant Omicron is different from Delta and should we worry about it

The new variant of COVID-19 which has been named Omicron by the World Health Organisation and declared 'Variant of Concern' is a matter of research for scientists across the world. The new variant which was first detected in South Africa is believed to be more dangerous than the previously known variants.

However, it was the Delta variant which scientists believe is twice as contagious as previous variants brought the deadly second wave of the COVID-19 in India during April-May and also wreaked havoc in several parts of the world with several cases of hospitalisation and deaths.

Delta variant currently accounts for more than 99% of cases of COVID-19 that are genetically sequenced in the United States, according to the Centers for Disease Control and Prevention. However, it remains to be seen whether Omicron will surpass the Delta variant in terms of its severity and only time and extensive research will give a clear answer.

Comparison between Omicron and Delta

Gene sequencing of the Omicron variant showed that it had more mutations than the Delta variant of COVID-19. 

Researchers found 43 aa mutations in the spike proteins of the Omicron as compared to 18 in the Delta variant. 

Omicron has more mutations on its spike protein than the Delta variant, but what it means remains to be seen.

The high number of mutations does not automatically mean that these variations are more dangerous.

But this simply means that the virus has further adapted to the human species by generating another variant.

Omicron variant has some similar mutations in its spike protein to the Delta, Alpha, Gamma and Beta variants

This means Omicron will also be very transmissible, likely enabling the virus to more easily get around antibodies.

This lowers the vaccine's efficacy against symptomatic COVID-19 disease.

In the Delta variant's case, scientists expect the vaccines to remain protective against severe COVID-19. 

South African scientists believe Omicron may lead to more cases of reinfection in people already infected before.

Vaccine effectiveness in Omicron and Delta

Globally, vaccines have been able to counter Delta, however the same cannot be said about the Omicron as of now.

A Lancet study showed Covishield was effective in fighting the deadly Delta variant during its surge and developed antibodies.

Scientists feel Omicron could render vaccines less effective as it shares several key mutations with Beta and Gamma.

These made Beta and Gamma variants less vulnerable to COVID-19 vaccines. However, this is still being researched.

The Omicron variant has 26 unique mutations, many of them in regions targeted by vaccine antibodies. 

Symptoms of Omicron and Delta variants

Symptoms seen in patients infected with the Omicron variant included fatigue, headache and a scratchy throat.

Doctors in South Africa say that like earlier cases there is no loss of smell or cough associated with the infection. 

But cough and loss of smell are now less common symptoms even in cases of infection with Delta variant unlike before.

Cold symptoms like a headache and runny nose are now more common symptoms of COVID-19, the latest research shows.

Anecdotal evidence shows that confirmed cases of COVID-19 caused by Omicron have caused mild symptoms.

But it should be noted that most of those infected with Omicron are the younger people, as per South Africa's health department.

In general, it's too early to make a claim that Omicron has better or worse symptoms than the Delta variant of COVID-19.