Saturday, 9 December, 2023

Omicron And Herd Immunity

Uttam Maharjan

The COVID-19 pandemic has been with us for a little over two years. There are no signs of the disease abating. Rather, it has been stronger in countries or places where it was inactive till some time ago. For example, it is surging in Bhutan, which had been able to keep the surge in the disease at bay. Likewise, some Pacific countries are also witnessing a surge in infections.

Despite the vaccination drive all over the world, no tangible success has been attained so far. It is clear like day that vaccination, coupled with the strict observance of health safety protocols, is the best way to develop herd immunity in people across the world. Vaccination helps strengthen the immunity by enabling it to develop antibodies. Antibodies are also developed through previous infections. Vaccines offer strong protection to people against the disease. But the antibodies so developed go on decreasing in effect with the passage of time. This is the reason why booster shots need to be given to the people already having received two doses in order to protect them from re-infection.

Mild variant
Omicron is the latest variant infecting people. The variant is highly transmissible. As such, when it emerged in November 2021, it infected far more people than Delta did. It also infected even those who had received not only two doses of vaccines but also booster shots. As Omicron is milder than other variants, including Delta, more and more people also recovered from the disease soon. The rates of death and hospitalisation from the variant are lower than those from other variants. The scenario in Nepal corroborates this. When Omicron surged in the country, more and more people got infected. At the same time, more and more people also recovered from the disease.

The rates of hospitalisation and death were also lower. It may be noted that those who are fully vaccinated develop mild illness if infected. They may recover soon as compared to those who have remained unvaccinated. However, when a virus spreads to people quickly, it undergoes mutation, producing other variants. The emergence of Omicron is also due to mutation. There is now a discourse in the scientific community on whether Omicron will lead to herd immunity.

Many scientists believe in the endemisation of COVID-19. They reckon that COVID-19 will eventually be like the flu. The disease will continue to appear in seasonal outbreaks but there will be no widespread outbreaks. As to the possibility of Omicron resulting in herd immunity, they are of the opinion that being a highly transmissible variant, Omicron, or any other variant, may not induce herd immunity in people. Dr. Don Milton at the University of Maryland School of Public Health opines that herd immunity is an elusive concept and not applicable to the coronavirus.
However, the World Health Organisation (WHO) strongly believes that herd immunity is possible in the case of the coronavirus, too. Herd immunity can be attained when a large segment of a population becomes immune to a virus and the virus can no longer spread to those who are not protected through vaccination or previous infections. For example, herd immunity against measles required 95 per cent of a community to be immune from the disease.

Vaccine equality is still a far cry. Rich countries have vaccinated most of their people, whereas low-income countries are struggling to obtain enough vaccines. In some low-income countries, even less than five per cent of the population has been vaccinated. Further, vaccine hesitancy seen in some developed countries as well as in poor countries has posed a challenge to the efforts at eliminating COVID-19.

The WHO is a strong advocate of vaccination. The world body has been trying to bring about vaccine equality across the world through the COVAX facility in collaboration with other partners. The world body also believes that herd immunity can be attained through vaccination and that allowing a disease to spread to any segment of a population will result in unnecessary infections and deaths. In fact, herd immunity can be attained through vaccination or exposure to the causative pathogen of a disease. Attaining herd immunity through exposure to the pathogen is very risky as it may result in innumerable infections and deaths.

Vaccines work without making people sick. Vaccines train the immune system to make proteins that fight disease. Such proteins are called antibodies. Vaccinated people are protected from contracting disease and transmitting it to other people, thus helping break the chain of transmission. This is the reason the WHO has been insisting on vaccination from the very beginning.

So the best option available for tackling COVID-19 is through vaccination together with the strict health safety mandates such as wearing face masks, using sanitiser or soap and water, maintaining social distancing and avoiding crowds or large gatherings. For the fair distribution of vaccines all over the world, rich countries can play a greater role. They should assist the WHO in enabling every country to lay its hands on vaccines in sufficient quantities. It is good to know that children are getting vaccines in some countries, including Nepal. The Centres for Disease Control and Prevention (CDC) has recommended that everyone five years old and above be vaccinated against the coronavirus.

When a large proportion of the world population is fully vaccinated, the coronavirus will be weaker and it will lose its capacity for spreading among people. When this happens, the chain of transmission will be broken and the virus will be like a flu virus. It can attack people but cannot assume epidemic or pandemic proportions. Let’s hope that such a situation will emerge soon.

(Maharjan has been regularly writing on contemporary issues for this daily since 2000.