Dr. Shyam P Lohani

A vast majority of the population of Nepal is yet to receive a full dose of COVID-19 vaccines. However, a debate has already started on whether those who received both doses of the vaccines need a booster dose. At the same time, the rapid spread of the Delta variant throughout the world and increasing reports of breakthrough COVID-19 cases are raising questions either fully vaccinated people should receive an additional booster dose to enhance their immunity.
An extra dose may be needed to fight off the more contagious viruses as well as to develop more prolonged immunity, although sufficient evidences have yet to come. A booster dose is an extra dose of a vaccine given after the initial course of vaccine to strengthen protection that may have started to wane.

Issues
Studies have shown that the Moderna vaccine remained 93 per cent effective through six months, just one percentage point less than the initial report. Similarly, research has shown the Pfizer-BioNTech vaccine to be 88 per cent protective against symptomatic cases of the Delta variant, while AstraZeneca’s vaccine was 67 per cent effective. There are a small group of people with weakened immune systems, such as transplant recipients, who are likely to need an extra shot sooner rather than later. Other groups of people with weakened immune systems are people receiving active cancer treatment for tumours or cancers of the blood, people who are taking medicine to suppress the immune system, people who received a stem cell transplant within the last two years, advanced or untreated HIV infection and those who are on active treatment with high-dose corticosteroids or any other drugs that suppress the immune response.
It is to be noted that the extra shot is not a traditional booster because people with weakened immune systems are less likely to get an adequate response to an initial dose of COVID vaccine, thus an additional booster dose may benefit them. For the rest of the population, a booster dose may prove to be beneficial if immunity wanes over time, or if new variants develop which scape vaccine protection. In the first scenario, administrating another dose of the original vaccine may be enough. In the second scenario, vaccines specifically developed against new variants may be needed.
Some countries are planning to give a booster dose using a vaccine-type that is different from the one people received initially. Chile recently announced plans to offer booster shots from AstraZeneca to people over 55 years of age and who earlier received the vaccine from different manufacturers like Sinovac. This mix-and-match strategy is known as heterologous boost, and there is some evidence that it can provide an advantage over an additional booster dose of the same formulation.
Israel became the first country to administer extra shots to its citizens over 60 years of age. Similar plans to give boosters to the elderly and people with certain health conditions have been announced by the United Kingdom, Germany, and France. Russia, Hungary, and the United Arab Emirates are offering their citizens a booster dose more broadly. Recently, the US Food and Drug Administration authorised an additional dose of the Pfizer and Moderna vaccines for certain people with compromised immune systems. In the future, booster shots for the general population starting with the elderly are likely to be approved by the health authorities around the globe.
Developed countries are getting vaccinated 20 times faster than nations with low and medium incomes. At the current rate of giving shots, it will take at least six months to cover 75 per cent of the world population. The World Health Organisation has called for a halt to booster doses until at least the end of September in order to enable at least 10 per cent of the global population to be fully vaccinated. Till now, more than four billion vaccine doses have been administered across the world. More than 80 per cent of inoculated doses were utilised by developed countries, although they account for less than half of the world’s population. Therefore, the provision made by some of the countries for a booster dose has raised ethical debates.
Proponents of initiating boosters argue to a preliminary research suggesting immunity provided by the vaccines may wane over time. It has been argued that the slow decrease of protection along with the increased danger from new variants such as the Delta and possible future variants, may not provide the same protection they thought to provide just a few months ago. Opponents argue that there is no scientific rationale for giving boosters to fully vaccinated people other than the immune-compromised. Even though breakthrough infections have increased, they argue, the vaccines are still meeting their primary purposes as preventing severe illness and deaths from COVID-19.

Terrible strategy
It is a terrible strategy for ending the pandemic to give vaccinated people in developed nations a minimal boost in immunity while billions of people in developing countries are still completely unprotected. No one is safe until everyone is safe has become the mantra for an endeavour to end the COVID-19 pandemic with good reason. High transmission among the susceptible populations may lead to mutations which in turn provide opportunities for the emergence of new, more transmissible and pathogenic variants that could escape natural or vaccine-induced immunity. Therefore, it is ethically and scientifically wise to scale-up of vaccination drive before the widespread booster campaigns.

(Prof. Lohani is the founder and academic director at Nobel College. lohanis@gmail.com)