Lifting non-pharmaceutical interventions following the COVID-19 pandemic – the quiet before the storm?

ABSTRACT

Introduction

In the first months of the novel coronavirus (COVID-19) pandemic that begun in 2020, non-pharmaceutical interventions (NPIs) have been adopted worldwide. However, the effects of NPI implementation go beyond slowing the spread of COVID-19. Here, we review the non-intended effects that may have arisen from prolonged application of NPIs.

Areas covered

NPIs also affected the epidemiology of other infectious diseases, with unprecedentedly low circulation of several respiratory and gastrointestinal viruses being observed worldwide in 2020. While this was a welcome effect for already strained health-care systems, prolonged low exposure to pathogens may result in an increased pool of individuals susceptible to certain diseases. Out-of-season or unusually intense outbreaks of non-vaccine preventable diseases have already been documented as NPIs were gradually eased. In the context of widespread and important disruptions in national vaccination programs during the early phase of the pandemic, the risk of vaccine-preventable disease resurgence after NPIs are lifted cannot be excluded either.

Expert opinion

Awareness must be raised of the risk of vaccine-preventable disease resurgence, and efforts need to be made to mitigate this risk, where possible, by increasing vaccination coverage. Research and regulatory opportunities brought on by the COVID-19 pandemic should be seized.

Plain Language Summary

In the first months of the COVID-19 pandemic, the only methods available to slow the spread of the disease were non-pharmaceutical interventions, such as lockdowns, mask wearing, social distancing, school closures, and travel bans. Even after vaccines against COVID-19 became available, combinations of non-pharmaceutical interventions continued to be implemented by most countries, to various extents. Although these measures lowered the number of people who got sick before vaccines and therapies against COVID-19 were available, they also had other consequences for public health. The non-pharmaceutical interventions implemented worldwide have slowed or even stopped the spread of several infectious diseases: since 2020, fewer cases of flu, bronchiolitis, gastroenteritis, and other diseases were recorded compared to pre-pandemic times. This relatively long 2-year period during which people, especially children, were exposed to fewer infections might mean that their immune systems are less prepared to fight these diseases. In addition, vaccination against diseases other than COVID-19 dropped in the early months of the pandemic, meaning that the number of children and adults who are not protected against vaccine-preventable disease has potentially increased. Easing of COVID-19 restrictions has caused a comeback of some diseases against which no vaccine is available, sometimes with more cases than during the pre-pandemic years; there is a risk that this might happen with vaccine-preventable diseases as well. To prevent outbreaks, routine and catch-up vaccinations against other diseases besides COVID-19 should be encouraged and promoted.

KEYWORDS:

• COVID-19 pandemic
• infectious diseases
• influenza
• non-pharmaceutical interventions
• norovirus
• outbreaks
• respiratory syncytial virus
• resurgence
• rhinovirus
• vaccine-preventable diseases

Article highlights

• Non-pharmaceutical interventions (NPIs) such as lockdowns, movement restrictions, mask mandates and school closures, adopted during the COVID-19 pandemic, also led to unusually low burdens of both vaccine-preventable and non-vaccine preventable (VPDs and non-VPDs) infectious diseases, including influenza, respiratory syncytial virus (RSV), pertussis, measles, rotavirus, and norovirus

• While this effect of NPIs was beneficial for already strained health-care systems, it also translated into reduced opportunities for natural boosting of immunity against those pathogens, potentially leading to an increased pool of individuals susceptible to diseases

• In addition, transient disruptions of varying magnitude in vaccination programs have been documented in several countries, which could further contribute to the decreased community immunity elicited by prolonged low exposure to pathogens

• Activity of influenza and other VPDs continues to be low at the beginning of the third pandemic year, while for non-VPDs, such as RSV and norovirus, out-of-season outbreaks of high intensity have been documented following easing of NPIs, suggesting that infectious diseases might resurge once restrictions are lifted

• VPD outbreaks could be prevented by increasing vaccination coverage, unless awareness of health-care providers and the general public regarding the risk of infectious diseases is lowered following long periods of low disease burden in the pandemic era

• The COVID-19 pandemic has also brought on several opportunities that should be seized; these include the possibility to establish adult vaccination registries, to conduct research on long-term immunity against influenza, to streamline the vaccine development and regulatory approval processes, and to perfect strategies of epidemic/pandemic preparedness for the future

Acknowledgments

Authors thank Modis for editorial assistance, manuscript coordination, and design support on behalf of GSK. Timea Kiss provided medical writing support, Gil Costa provided design support, and Emilie Mak Fan coordinated manuscript development.

Author contribution

All authors contributed to the interpretation of the data and a critical review of the paper for important intellectual content. All authors are in agreement with the content of the final article and have approved it for submission and publication.

Declaration of interest

KB Oh, TM Doherty and V Vetter are employees of the GSK group of companies and hold shares in the GSK group of companies as part of their employee remuneration and they have no non-financial competing interest to declare. P Bonnani declares payment and support from the GSK group of companies, MSD, Pfizer, Seqirus, Astra Zeneca, Janssen, and Sanofi Pasteur. Authors declare no other relevant financial and non-financial conflict of interest that the ones disclosed above.

Reviewer disclosures

Peer reviewers on this manuscript have no relevant financial or other relationships to disclose.

Additional information

Funding

This work was funded by GlaxoSmithKline Biologicals SA. GlaxoSmithKline Biologicals SA was involved in all stages of the conduct of this review and covered the costs associated with the development and the publishing of the present manuscript.