View: Is Omicron a signal for 3rd COVID-19 wave?

Menon says that Omicron is a variant of concern because where it has been seen to spread, such as in the Gauteng province of South Africa and now more broadly across that country, it has displaced the Delta variant as the main circulating virus strain. This suggests that it has specific advantages over that strain.

The variant seems to be more transmissible and is able to evade prior immunity. "However, it isn't clear that it is leading to significantly more symptomatic disease or more severe outcomes among the vaccinated. For this reason, it is hard to assess its impact at the moment and we just have to wait for more data to come in," says Menon.

Scientists are trying to collate the limited study and available data on Omicron. The Omicron variant has a large number of mutations which may mean the virus acts differently from other variants that are circulating. It will take time before there will be clear evidence to determine if there is any change in the transmission of Omicron compared to other variants, how the variant responds to existing therapeutics, or whether infection or re-infection with Omicron causes more or less severe disease.

According to WHO many studies are needed, including assessments of transmissibility or ease of spread of Omicron from person to person as compared to the other variants. Studies and extensive research have to be done on the severity of infection and re-infection with the new variant, performance of the current Covid-19 vaccines, the performance of diagnostic tests including the antigen tests to detect infection with Omicron and the effectiveness of current treatments for the management of patients with Covid-19 disease.

There is every reason to be cautious, as with every new variant. However, unless we understand how disease caused by this variant affects those of different age groups, those with a prior vaccination, or with comorbidities, etc., it is impossible to say more about whether it poses a genuine threat. We hope to understand this in the coming days.

Prof K Srinath Reddy, a cardiologist and epidemiologist and the President of the Public Health Foundation of India (PHFI), says that the delta variant appears to have waned in India, though it may resurface in crowded areas involving the under-vaccinated population groups. The imminent threat appears to be that of Omicron which has the potential to spread rapidly. Though early indications are of milder illness, the impact on elderly persons and immunocompromised individuals is not clear.

Researchers in South Africa and around the world are conducting studies to understand many aspects of Omicron.

According to WHO, it is not yet clear whether Omicron is more transmissible compared to other variants, including Delta. The number of people testing positive has risen in areas of South Africa affected by this variant, but epidemiologic studies are underway to understand if it is because of Omicron or other factors.

It is not yet clear whether infection with Omicron causes more severe disease compared to infections with other variants, including Delta. Preliminary data suggests that there are increasing rates of hospitalization in South Africa, but this may be due to increasing overall numbers of people becoming infected, rather than a result of specific infection with Omicron.

There is currently no information to suggest that symptoms associated with Omicron are different from those from other variants. Studies are ongoing to determine if there is a change in how easily the virus spreads or the severity of the disease it causes and if there are any impacts on protective measures.

According to the US's Centers for Disease Control and Prevention(CDC) the Omicron variant is likely to spread more easily than the original SARS-CoV-2 virus but how easily this variant spreads as compared to the Delta remains unknown. CDC maintains that anyone with Omicron infection can spread the virus to others, even if they are vaccinated or don’t have symptoms.

WHO is working with technical partners to understand the potential impact of Omicron on vaccine effectiveness. Researchers are assessing the performance of current vaccines against Omicron.

The Indian Medical Association (IMA) has issued a warning about the third wave of the coronavirus disease (Covid-19) hitting the country if necessary precautions are not taken amid the surge in Omicron cases. With the scientific evidence available and the experience noted in countries of origin, it is evident that the Omicron variant will have high penetrability and will affect more people.

Manindra Agrawal, an IIT Kanpur professor has already predicted that a mild third wave of COVID-19 is likely to peak in India between January and February next year. He is a co-founder of the government-backed Sutra model which was used to mathematically project the trajectory of the pandemic in India.

"Evidence so far suggests that there will be a mild third wave in India early next year. As observed during spread of Delta, a mild lockdown (night curfew, restrictions on crowding) can bring down beta substantially. That will significantly reduce the peak value."

Agrawal says that hospitalization load could be even lower as there are indications that the cases are mostly mild. But there is a need to wait for more data to be sure.

Menon also maintains that the immunity provided by the antibodies wanes with time. However, there are other components of the immune system, including T-cells and B-cells which maintain immune memory of a prior infection. The hybrid immunity that is expected for much of the Indian population should be protective against severe disease.

"I expect that cases will rise by early next year, but do not think that will have the sort of impact on mortality that the second wave had nor that we will see the steep rise that we saw in the second wave. We will have to wait for more data to be able to project this."

Lahariya also believes that a third wave cannot be ruled out for India; however, epidemiologically speaking, any subsequent wave in India would be far smaller than the previous ones. The number of cases and even the number of hospitalisations will be lesser.

"The emergence of Omicron is a reminder that the pandemic is not over yet and there is a need to review the preparedness and response at every level. The Indian government should seriously consider to commission an independent review of the pandemic response in the last 21 months," says Lahariya.