COVID-19 vaccine booster strategy against Delta variant evidence of growing inequity, says WHO

By Dr. Liji Thomas, MDJul 14 2021

The emergence of the novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has led to the global spread of coronavirus disease 2019 (COVID-19). Over 187.99 cases and over 4 million deaths have been reported since the virus was first detected in Wuhan, China, in December 2019.

The virus is also mutating at a rapid pace, with several of the changes in the genomic sequence causing gain-of-function in the form of increased infectivity, higher transmissibility, immune evasion, and possibly greater virulence.

In the absence of effective antivirals to counter the virus, the focus has been on the development and prompt rollout of vaccines. Amazingly, the first two vaccines, built on a messenger ribonucleic acid (mRNA) platform, obtained emergency use authorization (EUA) within a year of the onset of the pandemic.

Study: COVID-19 booster strategy as Delta multiplies, highlights ‘disappointing inequality’: WHO. Image Credit: LookerStudio / Shutterstock

This was followed by the approval of over a score of other vaccines, most with high efficacy against the virus. Vaccines were rolled out in many countries, notably the UK, Israel, and the USA, which have achieved impressively high vaccine coverage.

Emerging VOCs

However, low-income countries have been left out of the race, and are still struggling with high caseloads, shortages of essential equipment and therapeutic agents. The spread of the virus threatens to outrun vaccine-derived immunity, as it morphs into many different variants of concern (VOCs) that exhibit resistance to antibody-mediated neutralization.

The latest VOC to show a rapidly rising incidence worldwide is the delta strain, already found in over a hundred countries. Along with the alpha and beta variants, it is poised to spread with unprecedented speed.

Delta and other highly transmissible variants are driving catastrophic waves of cases, which are translating into high numbers of hospitalizations and death,” says the head of the World Health Organization (WHO), Tedros Adhanom Gebreyesus.

This variant is spreading among both vaccinated and unvaccinated populations, but in the latter, it causes a higher proportion of symptomatic cases that can quickly overwhelm health services and prevent lives from being saved by timely medical care. So rapid is its increase that the WHO says it will probably be the dominant strain globally, in the very near future.

Even countries that successfully managed to ward off the early waves of the virus through public health measures alone, are now in the midst of devastating outbreaks,” comments Gebreyesus.

Vaccines are effective

Citing this, vaccine companies are producing booster shots to extend coverage to these strains. And, says Gebreyesus, “Some countries and regions are actually ordering millions of booster doses before other countries have had supplies to vaccinate their health workers and most vulnerable.”

As of now, says WHO Covax co-lead Ann Lindstrand and WHO Chief scientist, Dr. Soumya Swaminathan, two doses of any WHO-approved vaccine provide high protection against symptomatic COVID-19. Despite the fact that the delta strain is causing many infections in populations that have already received the vaccine, most of these are mild and do not require hospitalization.

“The people in the hospitals are unvaccinated,” explains Swaminathan. Therefore, the decision to channel vaccines into boosting immunity in those already vaccinated should be made on the basis of real-life data, rather than the propaganda put out by companies.

Gebreyesus underlined this warning, saying that instead of vaccine manufacturers Moderna and Pfizer prioritizing the supply of third doses of the vaccine to already vaccinated populations, they should go all out to supply global vaccine providers such as the COVAX global initiative, the Africa Vaccine Acquisition Task Team, and low-middle income countries.

“Enlightened self-interest”

The scale of the outbreak that is occurring, and its worsening trend promises to delay global recovery, whether in the area of health or of economic reopening. While the obvious emergency has shifted to developing countries, Gebreyesus provides a reminder that even those countries that have already achieved a relatively high vaccine coverage that the whole world is not out of danger yet.

Countries vaccinating their population are starting to say, ‘we have managed to control this, so it is not our problem.’ They ignore the rest of the world and give the virus a chance of circulating.”

Terming it “enlightened self-interest,” Gebreyesus explains that the virus will continue to circulate as long as the pandemic goes on – as long as countries remain unvaccinated. The obstacle to united action is greed, he says.

Sharing resources

The WHO Director-General also pressed for sharing of licenses and technology to expand vaccine production into the rest of the world. Citing the example of AstraZeneca, which has set up production in India, Korea, Australia and Japan, and is planning to begin still more plants, Tedros explains that this will allow COVAX, the global vaccine initiative, to gain access to the hundreds of millions of doses that are necessary to vaccinate low- and middle-income populations.

As of now, the doses that are being donated are at least an order of magnitude lower. Gebreyesus says what is needed is an “all-out, no regrets accelerated building up of new vaccine manufacturing hubs.” Many countries today have the funds to pay for vaccines, but the shortage in supply denies them access. Thus, he calls for global leadership to expand vaccine production quickly.

He concludes that united global effort will be essential to extinguish the “pandemic inferno” because putting it out in spots will allow the fire to smolder everywhere, with the result that “sparks will eventually travel and grow again into a roaring furnace.”