# Macau study of 1.88 million influenza tests links post-pandemic excess to immunity debt

- Published: 2026-11-14 00:58 UTC
- Section: Life & Health › Medicine
- Tags: influenza transmission, immunity debt, post-pandemic influenza, Macau influenza tests, SEIRS model, convergent cross mapping, influenza A, influenza B, multi-source surveillance, Nature Communications
- URL: https://realtech.media/news/rt-18953f57b6c16ac8a5a340a3_macau_study_of/

**Analysis of ~1.88 million influenza tests from Macau (2010–2025) shows a post-pandemic excess consistent with immunity debt; the authors describe a regime shift, not a return to baseline.**

![Macau study of 1.88 million influenza tests links post-pandemic excess to immunity debt](https://realtech.media/media/2026/11/18919251a08f5428.jpg)
*bioengineer.org*

Researchers from Macao Polytechnic University, Kiang Wu Hospital and partner institutions analysed about 1.88 million clinical influenza tests collected in Macau from 2010 to 2025. They combined these with meteorological data, air quality records and digital information-seeking data, and with independent surveillance and time-resolved viral genomes from Hong Kong. The results were published in Nature Communications and are available via doi.org [1]. The data were benchmarked against global surveillance data [1].

## Immunity debt and population susceptibility

Counterfactual inference indicates a post-pandemic excess in influenza activity consistent with immunity debt, mirroring global resurgence patterns [1]. An independently parameterised susceptible–exposed–infectious–recovered–susceptible (SEIRS) model reproduces this excess [1]. The best-fit debt fraction is 42%, and the approximate Bayesian computation posterior is 58% with a 95% uncertainty interval of 32–77% [1].

According to the authors, susceptibility rose disproportionately in adults rather than in children [1]. Vaccination coverage in high-risk groups did not decline. The authors say this argues against reduced vaccine uptake as the driver of the resurgence [1].

## Environmental decoupling and reintroduction

Time-varying models and convergent cross mapping reveal what the authors call environmental decoupling. High susceptibility weakens meteorological constraints and sustains influenza A transmission, while influenza B is suppressed asymmetrically [1].

Spatiotemporal and phylogenetic evidence supports travel-linked reintroduction of the virus from ports of entry into dense neighbourhoods [1]. In addition, digital information-seeking shifted from a lagging to a leading indicator of clinical burden [1].

The authors conclude that these findings indicate a post-pandemic regime shift in influenza dynamics rather than a return to historical baselines. They state that this motivates adaptive, multi-source surveillance in high-density cities [1].

## Sources

1. [doi.org](https://doi.org/10.1038/s41467-026-79600-8)
2. [bioengineer.org](https://bioengineer.org/post-pandemic-immunity-debt-reshaped-urban-influenza-transmission-dynamics-study-finds)

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Source: RealTech, realtech.media — https://realtech.media/news/rt-18953f57b6c16ac8a5a340a3_macau_study_of/