Fri, Feb

Achieving herd Immunity In The Era of Vaccine Hesitancy

Thoughts From Afar
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Since the start of the COVID-19 pandemic, there has been an acceptance that the only way to end it and return society to some sense of normalcy was going to be through the discovery of viable vaccines.

Robert Sears in “The Vaccine Book: Making the Right Decision for Your Child” states “most anti-vaccine books claim that all shots are bad, the diseases aren’t really anything to fear, and as long as you live a natural and healthy lifestyle, you don’t have to worry. I think this is a very irresponsible approach to the vaccine issue. Vaccines are beneficial in ridding our population of both serious and nonserious diseases.”

Since the start of the COVID-19 pandemic, there has been an acceptance that the only way to end it and return society to some sense of normalcy was going to be through the discovery of viable vaccines. Fortunately, just a year into the pandemic a combination of science, bold political decisions and collaboration between big pharma and academia have delivered. As of the time of writing, eleven new vaccines have received Emergency Use Authorisation (EUA) from regulatory bodies around the world.

Phenomenal as this is, there are concerns regarding the integrity of the vaccine supply chain and equitable distribution of these vital products especially to less well-resourced countries, be it from the financial or scientific standpoint. Whilst global leaders in politics, health and civil society work to address these concerns, an even more pressing issue seems to be working against the likelihood of these vaccines ensuring that herd immunity is achieved.

The looming issue I refer to is vaccine hesitancy. In January 2019, the World Health Organization (WHO) named vaccine hesitancy as one of the top ten threats to global health. They further stated that addressing vaccine hesitancy required not just an understanding of the magnitude of the problem, but also a diagnosis of the root causes, tailored evidence-based approaches to addressing hesitancy, and monitoring and evaluating the interventions. As with many things, this call was broadly ignored. What the world did not know was that eleven (11) months down the line, the SARS-CoV-2 virus will send the world in a high-speed hunt for vaccines, only to be confronted with the potential roadblock we had opted to ignore.

Compounding this further is the fact that antibodies produced due to wild exposure to the virus have been found to wean. Available data suggests that the antibodies last between 3 and 8 months, and most people who test positive for SARS-CoV-2 are found to be devoid of antibodies after 5-months. The only viable route to herd immunity therefore has become through the use of vaccines.

Herd immunity is a form of indirect protection from infectious disease. It is obtained when a sufficient percentage of a population has become immune to an infection, whether through vaccination or previous infections, thereby reducing the likelihood of infection for individuals who lack immunity. For COVID-19, the attainment of this protection through wild exposure of the population has long been discounted because of its potential to cause extensive morbidity, leading to overburdening of health systems which then results in significant mortality.

With the original strain of SARS-CoV-2 known to have a reproductive number of 3, it is estimated that to achieve herd immunity, 75% of any given population must be vaccinated. With the new more contagious strains such as the Kent variant (B.1.1.7), the percentage of the population requiring immunisation increases to approximately 82%. To achieve this, there must be the availability of enough vaccines and the willingness of the population to get inoculated.

Apart from the vaccine supply chain constraints and nationalism that seems to have plagued the initial vaccine rollout, none of the currently registered vaccines is licensed for humans below the age of 16-years. Therefore, to achieve herd immunity, countries will have to aim at getting 75% of their population from those above 16-years. This is not a huge worry for countries with an ageing population who disproportionately have also been burdened with hospitalisation and deaths through this pandemic.

For example, according to data available from the United Kingdom’s Office of National Statistics (ONS), the number of people below age 16 constitutes 19.01%. This means, the country has a route to herd immunity without needing to vaccinate this segment of the population. For many countries in Africa however, this is not the case. A look at Ghana’s population profile indicates that 37.2% of the population is below age 16. Thus, with the current crop of vaccines, there is no viable route to inoculating 75% of the population unless further data is obtained to ensure that the age specifications of EUA are lowered.

The said data could become available if countries with much younger populations collaborate with vaccine developers and researchers to undertake further clinical trials in children. We cannot expect to sit on the fence whilst other countries use their young citizens as trial subjects. We need to be at the table where the next stage of this pandemic fight will be fought. It will be disingenuous if we do not, and then turn around to call for equity in vaccine distribution when the science is concretized. To do so will be akin to going to equity with soiled hands. The question is if parents of these children have misgivings about these vaccines, how can one expect them to give consent for their children to be part of any vaccine trials?

On this basis, we believe unless the threat of vaccine hesitancy is addressed head-on, many countries in Africa will be caught pants down in the reopening of the global economy.

The truth is, it is unlikely all 62.8% of Ghana’s population can be protected, assuming vaccines were readily available, without significant community engagement that understands and addresses any misconceptions. This is why we hold the view that based on the arithmetic, community engagement to debunk the misconceptions that are being spewed by the antivaccination brigade must be stepped up. The consequences of not doing so are grave. It is our view that this should become a national as well as the personal priority of those with the requisite knowledge. We are at a point where the pandemic fight is dual, one against the virus and the other against misconception. As we have argued often, we are in the era of self-preservation and all hands must be on deck.


Edited by Winifred Awa

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