Reflecting on 2022: Five Trends in Infectious Disease

The world has changed over the past year: the pandemic and resulting advances in vaccine technology have consequences that will also influence us in 2023 and future years. As 2022 has drawn to a close, here are some key trends in the infectious disease space and my take on what we might see continue into 2023.

Unprecedented advancement of new vaccine technologies

The COVID-19 pandemic put new vaccine technologies—especially mRNA vaccines —in the spotlight. RNA vaccines fulfilled their potential for rapid development and suitability for targeting SARS-CoV-2, a rapidly changing pathogen, suggesting that the technology may be useful for another rapidly changing pathogen, influenza virus. RNA vaccine technology continues to advance, and clinical trials for RNA vaccines targeting influenza viruses, coronaviruses, and other pathogens, including those causing emerging diseases, are underway. RNA technology is likely to be a critical tool in our kit of countermeasures against infectious diseases for years to come.

2022 also saw the success of structurally engineered antigens. The SARS-CoV-2 S glycoproteins expressed by RNA COVID-19 vaccines were structurally engineered, as were the antigens in respiratory syncytial virus (RSV) vaccine candidates that had successful pivotal trials. The key focus of antigen structural engineering was conformational stabilization for viral fusion proteins that preferentially present targets of neutralizing antibodies when locked in their prefusion conformations. Lack of prefusion stabilization of antigens in previous RSV vaccine candidates was a key cause of past vaccine trial failures.

Other technologies with great potential against bacterial diseases are also progressing at pace. For example, the Multiple Antigen Presenting System (MAPS) could potentially provide broader protection against pneumococcal disease based on its unique approach to making complexes of bacterial pathogens’ sugar chains and protein antigens to allow strong immune responses against more types of sugar chains as well as against pathogen-specific proteins.

The Resurgence of Respiratory Illnesses

2022 saw less social distancing and mask wearing than was practiced in 2020 and 2021, and common viruses, such as influenza virus and RSV, along with SARS-CoV-2, produced a particularly severe season of respiratory illnesses. RSV is the leading cause of pneumonia and bronchiolitis in infants and has no approved vaccine—though there are several candidates showing success in late-stage clinical trials. Some studies in older adults show an RSV morbidity and mortality burden that approaches that of influenza virus. With reduced herd immunity due to unusually light RSV and influenza seasons when COVID-19 prevention measures were being practiced, the 2022-23 RSV and influenza seasons started earlier than usual and have been the most severe in over a decade, and, of course, COVID-19 is still with us.

Shifting Clinical Trials Space

The pandemic-induced isolation of 2020 and 2021 accelerated the trend toward decentralized or remotely administered clinical trials. In contrast to the common practice of concentrating clinical trial sites in large cities, where academic medical centers are typically located, decentralization and remote administration increases the ability of people in more geographical regions to enroll and could help improve access, equity, and representation in clinical studies. Building off the decentralized ‘proof of concept’ trials of COVID-19 treatments and vaccines, the US FDA has now implemented initiatives such as Project Equity and Project Silver in the oncology space. The expansion of initiatives such as these could further accelerate the generation of evidence required to bring new vaccines to market.

Broadening Potential Vaccine Impact with Combination Vaccines

As we live in an increasingly interconnected society, there is an urgent need for broader coverage against multiple strains of pathogens or against multiple pathogens. For example, as university students return to communal living, there could be a resurgence in meningitis and other infectious diseases, for which current vaccines don’t protect against all responsible strains.

Increasing the availability of multivalent vaccines, with fewer individual injections needed despite a greater number of pathogens or variants targeted, could simplify vaccination schedules and reduce the number of children who miss their shots. As demonstrated by the recently rolled out COVID-19 bivalent boosters, new vaccine technologies like mRNA and MAPS increase the ease of making new combination vaccines, offering greater flexibility and agility to respond to changing variants or to protect against more strains of a disease agent.

Looking Ahead

This year, we’ve seen surges in common respiratory illnesses and also glimpsed the future of vaccinology. The achievements of the COVID-19 pandemic vaccines are just one example of what’s possible. In the coming years, the ingenuity that marked the pandemic response promises to expand our ability to prevent even more infectious disease.