Omicron is here. Various questions have naturally arisen. Does this new coronavirus variant spread more efficiently from an infected person to an uninfected person? If I am infected, will I be severely sick and need to be hospitalized? I am vaccinated; can Omicron still infect me?

On 25 November 2021, about two years after the first case of Covid-19 was reported and after different variants of the coronavirus – notably Alpha, Beta and Delta – resulted in over 26 crore cases and over 50 lakh deaths, Omicron was reported by scientists of Botswana and South Africa. It rapidly crossed continents. It has already been found in about 40 countries.

Several individuals in multiple cities in India have already been found infected. And, its further spread is being observed with each passing day. No one knows for sure whether Omicron can transmit more easily than the Delta variant that arose in India and has already infected crores of people throughout the world. Some initial observations indicate that Omicron is highly transmissible.

In the Gauteng province of South Africa, of which Johannesburg is the capital, the number of persons infected on 1 December was about 8,500 which was more than 2.5 times the count five days earlier. It was estimated that an infected person was infecting more than two uninfected persons, which is an alarming rate. This is about twice the rate observed for the Delta variant in the same area, implying that Omicron can infect more than twice as many people as Delta during a period of time.

Although only a few persons in the U.K. are infected by Omicron, preliminary data suggests that the number is rising. A very large number of persons worldwide had been infected earlier with different variants of the coronavirus. A large number are also fully vaccinated. All these persons have attained some level of immunity; they have started to produce proteins that can protect them against infection.

They have developed virus-blocking antibodies, called neutralizing antibodies. Can Omicron still infect such persons? We don’t know yet for sure. It appears from some laboratory experiments conducted outside of the human body, but using human cells, that Omicron can resist the neutralizing antibodies. Even so, persons with high or even a moderate level of neutralizing antibodies will be protected from severe Covid-19. Several individuals infected by Omicron, of whom a few individuals were known to be previously infected and/or vaccinated, only suffered from mild symptoms.

There is no firm evidence yet that the current vaccines may not work. Therefore, getting ourselves vaccinated protects us from severe disease even if current vaccinations are found not to protect us from being infected by Omicron. When a coronavirus infects a person, it replicates. In other words, the virus rapidly makes copies of itself after it infects someone. During this process little changes, called mutations, in its genetic material (RNA) occur naturally. A new variant evolves if these changes persist in the replicating coronavirus.

There are indications that Omicron arose in an individual who was infected with the Delta variant for a very long time. Changes in the virus accumulated and persisted in this individual. Thus, arose Omicron. When this person infected some others, Omicron started to spread. We have become lackadaisical in protecting ourselves. Keeping physical distance among ourselves has become difficult after restoration of normal activities.

However, we have stopped wearing masks. We are inviting trouble, perhaps paving the way for another wave of infection and resultant lockdown. We have to continue to protect ourselves using masks, washing hands, sanitizing and vaccinating.

(The writer is National Science Chair, Government of India)