Backed by Science: Here’s How We Can Eliminate COVID-19
Masked travelers in a metro in February 2021. Two years after the start of the pandemic, the war against COVID-19 is still not over.

As the WHO Executive Board resumes talks this week on a much-discussed Pandemic Accord, and other preparedness measures, three noted infectious disease experts chart a course for “eliminating” SARS-COV2 – warning that will take more sustained global coordination and determination than what has been seen so far.

At the outbreak of World War 1 in August 1914, enthusiastic patriots on both sides were assured it would be over by Christmas. At the declaration of the COVID-19 pandemic in January 2020, there was a general assumption that life would be back to normal by Easter. In neither case did events pan out that way. War-weariness and its modern equivalent, pandemic-weariness, have set in.

Each time there is a new wave of the pandemic, there is a strong desire to believe that if we can just get past this crisis, things will be better, the pandemic will come to an end and we can return to a normal life.

Those hopes have peaked again recently with predictions from some quarters of a “reprieve” after the peak of the Omicron crisis passes.

Reality check

A health worker wearing personal protective equipment (PPE) carries a patient suffering from the coronavirus disease (COVID-19) outside the casualty ward at Guru Teg Bahadur hospital, in New Delhi, India in April 2021, at the height of the Delta variant surge.

Unfortunately, as pointed out by Dr Anthony Fauci, Chief Medical Advisor to the US President, at the World Economic Forum on Tuesday, this optimism is not well-founded. Empirical evidence about the course of the pandemic and evolution of the SARS-CoV-2 virus show that this wish is not likely to become a reality.  It is time to look beyond the current crisis towards an endgame for this pandemic. We propose here a “vaccine plus” strategy that is based on three pillars – current and new tools, embracing the central importance of preventing airborne transmission and a major shift in attitude to equity.

There is a widespread view that extensive transmission of the currently dominant Omicron variant of SARS-CoV-2 will bring an end to the pandemic by harmlessly inducing herd immunity. This is unjustified and dangerous thinking. It does not provide a sound basis for immediate or long-term pandemic management.

Omicron and outcomes

Intubated Covid-19 patients in Brazil in June 2021. Omicron has fewer lower respiratory effects – but new variants may yet appear.

Although Omicron is less prone to cause pneumonitis (lung inflammation) and as a result has lower fatalities and number of people on ventilators, it causes severe consequences in some people – especially those who are vulnerable due to co-morbidities or other factors that impair the efficacy of vaccination, such as need for immunosuppressive therapy. With very high numbers of people contracting COVID-19, even relatively uncommon bad outcomes (death or permanent disability) will occur in large numbers, including in people without underlying health conditions. This is why, right now, hospital systems the world over are overwhelmed.

Immunity and reinfection

SARS-CoV2 under the microscope

Natural infection does lead a temporary immune response, including an immune response boost in those with pre-existing immunity due to vaccination or previous infection. This usually leads to recovery in the affected individual and eventually the end of the wave in the affected community. However, there have been four waves of COVID-19 over two years. Reinfection is known to occur and there is evidence that neither natural infection with SARS-CoV-2 nor vaccination leads to sustained protection against COVID-19. Hence, long-term protective herd immunity cannot be achieved by “letting it rip”. Over time the community will again become susceptible to the next wave.

There are two secondary issues here. Some infections, or vaccinations, such as measles, chickenpox, and polio, do induce long-lived immunity but others, like influenza, the common cold virus and SARS-CoV-2 do not.

With SARS-CoV-2, early evidence also suggests that the best vaccines seem to be more effective than natural infection alone at inducing an immune response and, of course, the vaccines induce that response with a hugely lower risk of adverse effects and death. 

Scientist conducting coronavirus vaccine research at the United States NIAID’s Vaccine Research Centre, Moderna’s original collaborator on the SARS-CoV-2 vaccine.

Moderna and Pfizer have indicated that their new Omicron-specific vaccines will be ready to present to regulators in March this year. The current rapid spread of Omicron may be due to immune evasion rather than any innate increase in transmissibility. If this is the case, then an Omicron-matched vaccine would have substantial impact. So, although widespread natural infection can induce an immune response, it will not produce sustained widespread protective immunity and does result in substantial harm. Vaccination is the only route to achieving herd immunity, and the pipeline is dynamic with many innovations to come.

Risk of COVID-19 variants

Massive numbers of people affected in non-immune populations, together with chronic infection in some immunosuppressed individuals, increase the risk of new variants emerging. Natural selection, the biological basis of evolution, means that variants that are “successful” will be even more transmissible than the current dominant strains. Whenever uncontrolled transmission is occurring somewhere in the world, new SARS-CoV-2 variants that can escape from existing immunity and cause a further global wave of COVID-19 disease will continue to arise across the world.

The only sustainable solution is to reduce the number of people getting COVID-19 and to do it everywhere. Even reducing the global burden by half would substantially reduce the likelihood of a new variant of concern appearing in a given time period.

Elimination of COVID-19

South Africa launched COVID-19 vaccination drives in schools in December 2021 as one response to the spread of the highly-infectious Omicron variant.

COVID-19 cannot be eradicated, but we can stop sustained community transmission. This status is known as “elimination”. In this situation outbreaks may still occur, but they do not become overwhelming. We have achieved this with measles.  We have no chance of even making progress toward this goal with COVID-19 without concerted and globally coordinated action. That action needs to achieve a low rate of transmission (R­eff < 1) simultaneously across the world.

We may not even have all the right tools just yet although some are on the way. Easy to administer tools (such as nasal sprays) as well as transmission blocking vaccines which are on the horizon and pan-coronavirus vaccines that are active against current and future variants and are currently in pre-clinical evaluation would greatly improve the feasibility of progress towards elimination. Many minds and skillsets will need to come together to consider the biology, epidemiology and technological solutions.

Equitable vaccination

COVID-19 vaccination, Democratic Republic of Congo

Clearly, the backbone of the response needs to be effective, equitable and acceptable vaccination regimens. Work will need to be done to optimise vaccine effectiveness and to overcome major barriers to distribution, including supply, cost and acceptance. It is worth noting that humanity lived with smallpox for centuries. Only a concerted global effort to vaccinate the world resulted in smallpox eradication and that took 20 years to achieve.

Some slippages in either the effectiveness of vaccination (such as the level of neutralising antibodies, population coverage due to refusal to accept the vaccine, etc) can probably be accommodated by implementation of additional measures to reduce airborne transmission. These measures include universal use of well-fitted N95 masks indoors and in close-contact outdoor environments, effective ventilation and filtration of indoor environments, and effective implementation of testing, tracing, isolation and quarantine (TTIQ) procedures using sophisticated AI-enabled tools. A tragic consequence of the sluggishness of national and international health authorities in accepting the singular importance of airborne transmission of the virus is that, two years into the pandemic, these simple and effective non-pharmaceutical interventions, and other actions to promote safe indoor air, still have not been universally adopted.

Global solidarity

We will need international cooperation at the highest level to design and implement this “vaccine plus” strategy, simultaneously, across the planet. Some global cooperation mechanisms exist, most notably the ACT-Accelerator. With a commitment to global elimination, we will need a quantum advance in supporting such a multi-lateral approach. Living with COVID-19 is not working.

A commitment to reducing numbers is our only way out. The longer we wait to shift gears and raise ourselves from our pandemic-weariness, the harder it will be. We need to look beyond the current wave. Rather than cross our fingers with a one-dimensional-vaccine only strategy, and a grossly inequitable one at that, we need to do the hard work to end the pandemic. The benefits of an elimination approach will come much quicker than people think; just halving COVID-19’s impact would change the world.

Guy Marks, Scientia Professor of Respiratory Medicine, University of New South Wales, the President of the International Union Against Tuberculosis and Lung Disease.

Brendan Crabb AC, Professor, University of Melbourne, is an infectious disease researcher, and Director/Chief Executive Officer of the Burnet Institute, which has played a major role in the COVID-19 pandemic, advising governments and advocating strongly for public health action. He is Chair of the Australian Global Health Alliance and the Pacific Friends of Global Health.



Raina MacIntyre is Professor of Global Biosecurity at The Kirby Institute, University of New South Wales.


Image Credits: Flickr: IMF Photo/Joaquin Sarmiento, Adnan Abidi/Flickr, Ninian Reid/Flickr, NIAID, Gauteng Department of Health, Gavi/2021/STARRY.

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