The current debate over the necessity, cost, and effectiveness of the third dose or "booster shots" for Covid is generating a lot of heat. The battle lines are clear. On the one side are the pharmaceutical companies, Pfizer, BioNTech, Moderna, and others who will benefit financially from the production, distribution and administering of booster shots in the USA and other first-world countries. Aligned on the other side are international organisations such as WHO and UNICEF, and advocates for vaccine equity.

The advocates for boosters point out that vaccination does not offer protection against the virus forever and a third dose enhances immunity. So far, so good! The jury is out on the issue of who needs the third dose and when. Also, with a global shortage of vaccines, a thorny ethical issue has resurfaced. Would the demand for a third shot increase the price and decrease the availability for those who are yet to receive their first dose?

If we take a global perspective, only a few of the people in low-income countries have been vaccinated. According to the Our World in Data project at Oxford University, just 31.7 percent of the world's population has received a single vaccine dose, while only 23.7 percent of people worldwide are fully vaccinated. In developing countries, a scant 10 percent of individuals have received a single vaccine dose. It is worse in Africa, where 25 people are dying each minute from Covid-19.

Last month, Israel became the first country to offer the coronavirus booster amid fears that vaccine efficacy dwindles over time. The UK has already authorised the booster, and the USA and other countries are likely to follow suit, raising fears that the imparity in global vaccine distribution would be further accentuated. The WHO has urged the US and other wealthy nations to wait until the end of this year and requested a four-month moratorium, to "give more people in other countries a chance to get a first dose of these lifesaving shots."

If we ignore the commercial side, the role and ferocity of the Delta variant in the "breakthrough cases" and the diminution of vaccine effectiveness have been the main drivers behind the third shot movement. According to an article published in Science, the mouthpiece of the American Academy for the Advancement of Science (AAAS), "The greater infectiousness of the Delta variant of SARS-CoV-2 has scientists and governments debating whether booster shots of Covid-19 vaccines are needed in some countries given limited vaccine supplies elsewhere."

The Science paper entitled, "Unethical? Unnecessary? The Covid-19 vaccine booster debate intensifies" also observes that, "as United States reveals its plan to offer an extra dose of Covid-19 vaccine, equity and scientific questions abound."

Studies show that even after five to eight months, vaccines still remain highly protective against severe illness, hospitalisation and death. In comparison, billions of the world's population have not received a single shot due to a shortage of vaccines. Consequently, one is faced with a moral and ethical dilemma. Do the less fortunate amongst us deserve a chance to live and avoid the inevitable fate once they get infected?

The WHO, the Coalition for Epidemic Preparedness Innovations, and Gavi, the Vaccine Alliance, have established Covid-19 Vaccines Global Access (COVAX) to procure and fairly distribute vaccines. But much of the vaccine development, production, procurement and distribution are ad hoc, generating controversy and inconsistency. Pharmaceutical companies have been criticised for knowledge hoarding, secret pricing, unreasonable profits, unfair bilateral deals and extortionate demands for indemnification against liability. COVAX has been criticised for an absence of transparency and accountability and for ignoring the need in Covid-19 vaccine distribution, according to a research paper in the science journal, Lancet.

Access to vaccines for all (and I mean all the people in the world) is fast becoming a global issue at all international gatherings, and has superseded climate change at the current General Assembly meeting in New York. This comes after 18 months since the pandemic first started because "it's clear the world is likely to be riddled with Covid-19—and its many variant successors—for years to come," according to a BBC report. "The next big question is whether two doses of each vaccine is enough" and when can we expect to have enough to vaccinate everyone, rich and poor.

"All indications are that [Covid-19] is going to become endemic, but the hope is that it can be managed through vaccines," said Flavio Torres, an economic epidemiologist at the University of Cambridge. "The practical policy at this point, given the low cost really should be to get as many people vaccinated as possible."

In light of these sentiments, WHO Director-General Tedros Adhanom Ghebreyesus late last month called for a moratorium on boosters, questioning the necessity of a third jab and highlighting the risk of "more potent" variants emerging in countries with "low vaccination coverage."

"We don't understand who is going to need a booster, how long after their last dose, or which vaccine combination works best," says physician-epidemiologist Bruce Aylward, a senior adviser at the WHO. "You need to understand all that before you decide how boosters should be used."

If everyone in high-income countries received boosters, that would use up one billion doses, Aylward estimates. "You're dealing with a finite, zero-sum resource," he says. "You are reducing supply for those who need it more."

In my final observations, I will offer some thoughts that my readers might also wish to consider. According to a report published by the Economist Intelligence Unit (EIU), "some features of the Delta variant mean that vaccines alone may not be enough to control the virus. Delta is far more transmissible than the original strain of the coronavirus (someone infected with Delta contaminates another 5-9 people, compared with 2-3 from the original strain). Israel, which has one of the highest immunisation rates in the world, illustrates how Delta is a game changer; after hope that the disease was under control, the country is now grappling with a fourth wave of cases."

The nations of the world must address the disparity in immunisation to minimise the loss in GDP and growth in poverty in Asia-Pacific, Latin America and Africa. In a Health Policy paper published in Lancet, eminent scholars and international experts point out that there are many dimensions of an effective global immunisation strategy against Covid-19. The paper, titled, "Challenges in ensuring global access to Covid-19 vaccines: production, affordability, allocation, and deployment" opines that an ethical approach to Covid-19 vaccine production and distribution should satisfy four uncontroversial principles: optimising vaccine production, including development, testing, and manufacturing; fair distribution; sustainability; and accountability.

"Having licensed vaccines is not enough to achieve global control of Covid-19: they also need to be produced at scale, priced affordably, allocated globally so that they are available where needed, and widely deployed in local communities," the experts said.

Dr Abdullah Shibli is an economist, and an information technology consultant. He is also a Senior Research Fellow at the International Sustainable Development Institute (ISDI), a think-tank based in Boston, USA.