Airfinity’s Dr Patricia Gallego highlights the persistent threat that COVID-19 continues to present to patients and healthcare systems around the world and outlines the urgent need for more vaccine breakthroughs in 2023 to combat the “tripledemic” burden of COVID-19, flu and RSV.


2023 will be a pivotal year for RSV but to reduce the level of pressure on hospitals and save lives, breakthroughs in COVID-19 and flu can’t come soon enough


In the eyes of many people, the COVID-19 pandemic is over and life has returned to normal. As we are now in the fourth year of COVID, its acute impact has passed and we are in a new phase of living with the virus.

It is now commonly referred to as the same as flu but this is a misconception. The burden of COVID is higher than flu and it impacts the population all year round.

The number of people hospitalised with COVID-19 is significantly higher than with flu. In the US, 340,000 patients were admitted in the most severe flu season, compared to 2.1 million people hospitalised with COVID-19 in what many consider to be the first year of the disease being endemic.

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While life may have returned to normal for many people, that is not true for healthcare systems and their staff around the world. Airfinity estimates the combined disease burden of COVID-19, flu and respiratory syncytial virus (RSV) will be three times greater than pre-pandemic levels next year.

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Before the pandemic, influenza and RSV alone caused over 200K hospitalisations in the US in one season. The pandemic greatly suppressed flu and RSV circulation for two winters. Last year’s 2022/23 season saw both return leading to more hospitalisations than in pre-pandemic years.

Next year we forecast a reduced burden from RSV and flu combined with similar levels for COVID. Overall respiratory disease hospitalisations are forecasted to be threefold pre-pandemic levels for the foreseeable future unless further progress is made in developing effective vaccines.

The direct impact of this is seen in the healthcare sector but it has wider economic implications too. Sick days by healthcare workers and the full employed population is estimated to have cost the US economy $62 billion in 2022.

The number of people classed as at high risk of severe COVID-19 is also forecasted to grow. Our analysis estimates the high risk populations in G20 countries will increase by 14% over the next ten years, resulting in more patients and pressure on hospitals.

Today’s vaccines for COVID-19 were a monumental success for scientists, governments and pharmaceutical companies. Saving an estimated 20 million lives in the first year alone and allowing the world to reopen and manage the virus in a sustained way.

The world now needs better vaccines. Today’s inoculations remain effective at preventing severe disease and death but they don’t prevent transmission or protect against changing variants and the protection garnered depletes over time.

The next generation of vaccines need to solve one or more of these problems. To break into the COVID-19 vaccine market now dominated by Pfizer/BioNTech and Moderna’s jabs, new vaccines need to offer protection against infection (e.g intranasal) or a more broader and durable protection. Combination vaccines such as those ones that target flu and COVID-19 could also reduce disease burden and change market dynamics.

There are currently 57 next-generation COVID-19 vaccines in clinical development. While we are still awaiting more definitive data on efficacy, the most progressed of these candidates largely use the same designs as the approved vaccines and therefore may also not offer a clear improvement over original vaccines. This means a significant advancement may still be far away.

Current influenza vaccines also have limited effectiveness against infection and transmission, driving the need for universal flu vaccines which have the potential to protect patients against infection and curb the virus’ spread. It’s been estimated that a universal flu vaccine with 75% efficacy against infection could reduce hospitalisations and deaths by 95%. There are now 68 preclinical and 11 clinical candidates in development, five of which are in Phase II trials.

The most exciting and imminent breakthroughs are against RSV. GSK and Pfizer are leading the race to bring an RSV vaccine to market this year. Both firms have released positive Phase III data in preventing lower respiratory tract disease in older adults. Pfizer’s vaccine has also been trialed as a maternal vaccine to protect newborn infants who are also at risk from severe disease.

If elderly RSV vaccines are approved and rolled out this coming autumn in the US, we forecast a reduction in hospitalisations of 15% this year. This impact is hindered by predicted low uptake of a new vaccine which we forecast will ramp up over time. Looking at the uptake of HPV and flu vaccines in the US, we estimate uptake will reach between 61% to 74% of the eligible population within seven years.

For the infant population, Pfizer’s maternal candidate and Sanofi and AstraZeneca’s newborn antibody shot Nirsevimab are also expected to be rolled out this year. Nirsevimab has shown to be 80% effective against preventing lower respiratory tract infections in all infants under 1 years old, offering protection for up to five months. Trial data indicates the Pfizer RSVpreF maternal vaccine demonstrates efficacy for 6 months. Strategic combination of both drugs would provide the greatest protection for infants throughout their first year of life when they are the most vulnerable to severe infection and hospitalisation.

If next generation vaccines are effective and widely rolled out, Airfinity modeling shows hospitalisations in the US from the tripledemic burden of COVID-19, flu and RSV could be reduced from an estimated 736,000 to 456,000 patients each winter. This figure could be further reduced if uptake of vaccines in the US population increased.

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There are many promising developments in the battle against respiratory viruses and the toll they take on people and healthcare. 2023 will be a pivotal year for RSV but to reduce the level of pressure on hospitals and save lives, breakthroughs in COVID-19 and flu can’t come soon enough.