Trends in invasive bacterial diseases during the first 2 years of the COVID-19 pandemic: analyses of prospective surveillance data from 30 countries and territories in the IRIS Consortium

David Shaw, Raquel Abad, Zahin Amin-Chowdhury, Adriana Bautista, Desiree Bennett, Karen Broughton, Bin Cao, Carlo Casanova, Eun Hwa Choi, Yiu Wai Chu, Heike Claus, Juliana Coelho, Mary Corcoran, Simon Cottrell, Robert Cunney, Lize Cuypers, Tine Dalby, Heather Davies, Linda de Gouveia, Ala Eddine DeghmaneWalter Demczuk, Stefanie Desmet, Mirian Domenech, Richard Drew, Mignon du Plessis, Carolina Duarte, Helga Erlendsdóttir, Norman K. Fry, Kurt Fuursted, Thomas Hale, Desiree Henares, Birgitta Henriques-Normark, Markus Hilty, Steen Hoffmann, Hilary Humphreys, Margaret Ip, Susanne Jacobsson, Christopher Johnson, Jillian Johnston, Keith A. Jolley, Aníbal Kawabata, Jana Kozakova, Karl G. Kristinsson, Pavla Krizova, Alicja Kuch, Shamez Ladhani, Thiên Trí Lâm, María Eugenia León, Laura Lindholm, David Litt, Martin C.J. Maiden, Irene Martin, Delphine Martiny, Wesley Mattheus, Noel D. McCarthy, Mary Meehan, Susan Meiring, Paula Mölling, Eva Morfeldt, Julie Morgan, Robert Mulhall, Carmen Muñoz-Almagro, David Murdoch, Joy Murphy, Martin Musilek, Alexandre Mzabi, Ludmila Novakova, Shahin Oftadeh, Amaresh Perez-Argüello, Maria Pérez-Vázquez, Monique Perrin, Malorie Perry, Benoit Prevost, Maria Roberts, Assaf Rokney, Merav Ron, Olga Marina Sanabria, Kevin J. Scott, Carmen Sheppard, Lotta Siira, Vitali Sintchenko, Anna Skoczyńska, Monica Sloan, Hans Christian Slotved, Andrew J. Smith, Anneke Steens, Muhamed Kheir Taha, Maija Toropainen, Georgina Tzanakaki, Anni Vainio, Mark P.G. van der Linden, Nina M. van Sorge, Emmanuelle Varon, Sandra Vohrnova, Anne von Gottberg, Jose Yuste, Rosemeire Zanella, Fei Zhou, Angela B. Brueggemann*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

11 Citations (Scopus)


Background: The Invasive Respiratory Infection Surveillance (IRIS) Consortium was established to assess the impact of the COVID-19 pandemic on invasive diseases caused by Streptococcus pneumoniae, Haemophilus influenzae, Neisseria meningitidis, and Streptococcus agalactiae. We aimed to analyse the incidence and distribution of these diseases during the first 2 years of the COVID-19 pandemic compared to the 2 years preceding the pandemic. Methods: For this prospective analysis, laboratories in 30 countries and territories representing five continents submitted surveillance data from Jan 1, 2018, to Jan 2, 2022, to private projects within databases in PubMLST. The impact of COVID-19 containment measures on the overall number of cases was analysed, and changes in disease distributions by patient age and serotype or group were examined. Interrupted time-series analyses were done to quantify the impact of pandemic response measures and their relaxation on disease rates, and autoregressive integrated moving average models were used to estimate effect sizes and forecast counterfactual trends by hemisphere. Findings: Overall, 116 841 cases were analysed: 76 481 in 2018–19, before the pandemic, and 40 360 in 2020–21, during the pandemic. During the pandemic there was a significant reduction in the risk of disease caused by S pneumoniae (risk ratio 0·47; 95% CI 0·40–0·55), H influenzae (0·51; 0·40–0·66) and N meningitidis (0·26; 0·21–0·31), while no significant changes were observed for S agalactiae (1·02; 0·75–1·40), which is not transmitted via the respiratory route. No major changes in the distribution of cases were observed when stratified by patient age or serotype or group. An estimated 36 289 (95% prediction interval 17 145–55 434) cases of invasive bacterial disease were averted during the first 2 years of the pandemic among IRIS-participating countries and territories. Interpretation: COVID-19 containment measures were associated with a sustained decrease in the incidence of invasive disease caused by S pneumoniae, H influenzae, and N meningitidis during the first 2 years of the pandemic, but cases began to increase in some countries towards the end of 2021 as pandemic restrictions were lifted. These IRIS data provide a better understanding of microbial transmission, will inform vaccine development and implementation, and can contribute to health-care service planning and provision of policies. Funding: Wellcome Trust, NIHR Oxford Biomedical Research Centre, Spanish Ministry of Science and Innovation, Korea Disease Control and Prevention Agency, Torsten Söderberg Foundation, Stockholm County Council, Swedish Research Council, German Federal Ministry of Health, Robert Koch Institute, Pfizer, Merck, and the Greek National Public Health Organization.

Original languageEnglish
Pages (from-to)e582-e593
JournalThe Lancet Digital Health
Issue number9
Publication statusPublished - Sept 2023

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© 2023 The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY 4.0 license


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