Uttam Maharjan

COVID-19 has been wreaking havoc in the world for over a year. The viral disease has been considered the most formidable disease of the 21st century. It has proved to be more dangerous than SARS and Ebola virus. The disease has upended the world economy, challenging human capacity for coping with it in an effective manner. The whole world is pulling out all the stops to contain COVID-19. Vaccines against the disease have been developed in a short span of time. The global vaccination campaign has been going on since the start of this year. Still, there has not been any remarkable progress in putting a curb on the disease.
Developing herd immunity is one of the mechanisms for controlling COVID-19. If herd immunity can be developed, all people, including those who are not immune to the disease, can be protected. A certain proportion of the population needs to be infected to spread a disease. It is called the threshold proportion. If the portion of the people immune to the disease exceeds the threshold proportion, herd immunity can be developed. It is called the herd immunity threshold.
The percentage of the population that needs to be immune to a disease varies from disease to disease. It also depends on the nature of a disease. If a disease is very contagious, a greater portion of the population needs to be immune to it. Usually, 50 to 90 per cent of the population needs herd immunity to lower the transmission of the disease. In case of COVID-19, experts say around 70 percentage of the population needs to be immune to it.

Protective antibodies
Experts say that there are two ways for stemming COVID-19. One is the natural method and the other is the vaccination method. Under the first method, enough people have to recover from the disease and develop protective antibodies against future infection. But there is the rub: It is still unknown how long such people can protect themselves from future infection. They can still contract the disease even if they have developed antibodies. As around 70 per cent of the population has to recover to make the natural defence system work, this may lead to many deaths, especially among older people and those with underlying medical conditions, and overwhelm healthcare systems. So adopting this mechanism for curbing the disease would be suicidal.
The other method is the use of vaccines. As under the natural method, vaccines also develop antibodies in people to enable them to fight future infection. The difference, however, lies in the fact that antibodies are developed in people without causing any disease or complications to them. History is witness to the fact that man has controlled such diseases as smallpox, poliomyelitis, diphtheria and rubella through vaccinations.
As far as COVID-19 is concerned, we have not reached the stage where herd immunity can be developed. As stated above, about 70 per cent of the world population (roughly 5.46 billion people) needs to be immune to the disease so as to reduce the infection rate. Attaining this much herd immunity depends on several factors. Progress in the vaccination drive, contagiousness of the disease and adherence to health safety protocols are the main drivers that would determine whether herd immunity can be attained. The more contagious the disease is, the more people need to be vaccinated against the disease. For this, the vaccination drive needs to be further accelerated.
As things stand, there is a problem with the global vaccination drive. Wealthy countries have hoarded vaccines in excess of their requirements, whereas poorer countries like ours are facing a shortage of vaccines. Our country initiated the vaccination campaign in January. But due to a shortage of vaccines owing especially to non-procurement of vaccines from India, the vaccination drive has hit a snag. There are around 1.5 people waiting for the second dose. When they will get the jabs is still in the air. However, the government is making efforts to procure vaccines from other countries like the USA, the UK, China and Russia.
Adherence to health safety rules is very important to attain herd immunity. Such rules should be followed by even those who have been vaccinated. If people strictly follow health safety protocols like social distancing, wearing masks and using sanitiser or washing hands with soap and water, the infection rate will decline soon. If people are indifferent to such protocols, the disease will be transmitted thick and fast. What is more, when the coronavirus spreads from one person to the other, it mutates. Mutated variants of the coronavirus have proved to be more dangerous with more transmissibility. Such mutated variants are responsible for giving rise to the second and third waves of the disease. Since the emergence of the second wave, both the infection and fatality rates have skyrocketed. It may be noted that even booster vaccines may be required to cope with mutated strains of the coronavirus.

Vaccination
It is a no-brainer that the higher the immunity, the better. As far as COVID-19 is concerned, we cannot afford to attain herd immunity through the natural method. Even if many adults can attain immunity, children and those with weakened immune systems like older people and those with underlying medical conditions may contract the disease. Vaccination is a sine qua non for developing herd immunity. For this, all the countries in the world should act in synergetic fashion and ensure fair and equitable distribution of vaccines. The COVAX initiative can be the best platform for this. What is important is that wealthy countries should support the global initiative. At present, it is facing problems with acquisition of enough vaccines for distribution to poorer countries, including ours.

(Former banker, Maharjan has been regularly writing on contemporary issues for this daily since 2000. uttam.maharjan1964@gmail.com)