Increase of Omicron cases in Mumbai and understanding various factors leading to this.

It has almost been a month since scientists in South Africa and Botswana found and warned the world of a new and the most contagious variant of SARS-CoV-2 named Omicron. What followed was a sharp rise in the number of infections, now confirmed in more than 80 countries, and the quest to understand this variant, its severity, and transmissibility.

Mumbai, a major city in the state of Maharashtra in India, has found itself as a hotspot for Omicron cases. Results of RT PCR tests in Bandra, Malad, Andheri, and almost the entire Mumbai showing a daily rise in positive cases. The state government has imposed and is reviewing the guidelines proactively. From imposing night curfew in the state to encouraging its citizens to be more complacent towards precautions, Maharasthra is home to the most number of cases in the nation.

But, the question remained, what made this increase of Omicron cases in Mumbai? The article tries to answer it by decoding Omicron along with the factors leading to the increase in cases in Mumbai.

Decoding Omicron

When around 50 mutations of the new variant Omicron were found in South Africa first, it was found that it can infect fully vaccinated people and also can reinfect those who have built antibodies and survived SARS-CoV-2. It was a grave concern, but researchers across the globe also wanted to look for a global trajectory of the mutations that will turn out in different countries. As Omicron spreads in more than 60 countries now, it is clear that this variant is the most contagious and capable of avoiding human immune defenses.

The two important factors to gauge the virus are how contagious or transmissible it is and how much it is capable of evading the immune systems. According to these two factors, it will be clear to predict how fast this virus can infect the global population and at what scale.

What is the transmissibility of a virus mean?

Transmissibility means the ability of the virus to replicate itself in human cells and spread from person to person. To better gauge the transmissibility of any respiratory virus, scientists look at how many people can get infected through one infected person at a given time. In short, the value of an effective reproduction number – R(t), where t represents the number of secondary infections along with seasonal weather nuisances, herd immunity, and public health interference of any given place for a person. A value of R(2) means a person has the ability to infect 2 other people, or R(4) means a person can infect 4 other people. So, according to this value, the contagiousness of a virus variant is calculated. In the case of Omicron, the situation is panicky, as the value of R(t) is gaining momentum and has even reached 3.7 in the UK, as reported by the UK health officials last week.

Since, it has been found that people who survived the earlier covid infections and built antibodies, were found to be reinfected with Omicron variant and also those who were fully vaccinated. So, it is clear that this variant also can evade human immune defenses. But, if a set of people are already immune to other variants, it will only allow the new variant to spread quickly, as the immune system will suppress the competing variants, as told by a renowned virologist and infectious disease modeler in the UK.

Another emerging theory of Omicron worth noting is its less severity and mortality rate. Scientists worldwide are finding that even though the Omicron virus transmits to human cells quickly, it is not creating a major issue to the lungs, which means the virus is traveling comparatively slow from the throat towards the lungs. This factor makes the variant or the carrier more prone to spreading it further to the population nearby, especially in highly dense population areas.

Factors leading to increase in cases in Mumbai

Population density and Mobility

Not only in India, but Mumbai is one of the most densely populated cities in the world. With 42% of the urban population in the city and around 41% of people living in slums; the population of Mumbai has more than doubled in 1991. It has played a huge role in Mumbai being the worst affected city from covid-19 as most citizens mass-travel through the city for a living. No wonder the positive results of the RT PCR test in Bandra and Andheri are leading in Mumbai city, given the trend of growing population in these areas.

International Passengers

Mumbai is also the busiest airport in India, after New Delhi. The influx of international passengers that Mumbai sees at its Chatrapati Shivaji Airport is akin to the rising number of cases. To curb this situation, the Uddhav Thackeray-led government had also put stricter rules to follow, more screenings of international and domestic passengers regularly. There have also been cases wherein the international returnees were tested negative on the arrival, but tested positive at home after a few days. This also resulted in more testing in the city, for instance, the number of RT PCR tests in Bandra, Borivali, and Andheri has seen a two-fold rise, which is a prudent move by the state authorities.

Flouting of Covid Norms and End of the year

Time and again, the local authorities, health officials keep encouraging the citizens to make social distancing, wearing masks at public places, and building better hygiene as a habit. Still, there are many instances where people are seen flouting the norms. In addition, the end of the year sees a major celebratory aura near Christmas and a new year. It surely needs a ramp up of the RT PCR tests in Bandra, and almost the entire Mumbai, to control an unpleasant situation at hand.

These were a few of the main reasons for the high number of cases in Mumbai. The silver lining, however, is that still, the numbers are under control, and following on the valuable lessons from the second wave, many diagnostic labs are doing sequencing and understanding the virus as soon as possible. One such company, SpiceHealth, which was at the forefront of India’s efforts to maximize testing that is also affordable since the pandemic began, is ensuring quality health services in Mumbai and other parts of the country. Getting an RT PCR test in Bandra, Worli, Andheri, or anywhere in Mumbai is just a click away, thanks to SpiceHealth. In welcoming efforts like these, there is also a need to do as much to avert the ‘third wave’ in the country.