Understanding the combined mental health impacts of flooding and COVID-19 in Hue City, Central Vietnam

Pham, Thi Dieu My; Hudson, Paul; Thieken, Annegret H.; Bubeck, Philip

doi:10.5194/egusphere-2025-3021

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https://doi.org/10.5194/egusphere-2025-3021

Preprints

01 Jul 2025

| 01 Jul 2025

Understanding the combined mental health impacts of flooding and COVID-19 in Hue City, Central Vietnam

Thi Dieu My Pham, Paul Hudson, Annegret H. Thieken, and Philip Bubeck

Abstract. Experiencing severe flooding tends to negatively impact mental health, creating a significant public health issue. Moreover, extreme events can co-occur, magnifying potential impacts. Understanding the combined mental health impacts of floods and COVID-19 is a research gap we addressed by conducting 400 face-to-face surveys in October 2023 in Hue City, Vietnam, where residents faced simultaneous flooding and COVID-19 in 2020.

The respondents' mental health was assessed using the Kessler psychological distress scale (K6), revealing that 20 % of the respondents experienced mental health distress, while 80 % did not report such distress. Binary logistic regression models demonstrated that among twelve flood stressors, facing ‘livelihood difficulties’, ‘seeing dead human bodies’, and ‘being rescued’ relate significantly to mental distress. Meanwhile, ‘impacts on individual health’ and ‘interrupted education’ are the two significant COVID-19 stressors. These five factors stay significant when combined. Additionally, a multivariable regression model revealed the combined effects of flood and COVID-19 when comparing the ORs of four groups ranging from ‘No flood stress & No Covid stress’ to ‘Flood stress & Covid stress’. The effect size is largest for those who experienced flood and COVID-19 impacts, followed by those who suffered only floods and those who faced only COVID-19, with the smallest effect size.

These findings underline the need to address public health problems caused by multiple risks, which is still a significant gap in developing countries. Furthermore, psychological impacts could be reduced by providing additional support to at-risk communities, like managing human remains, rehearsing evacuation plans, preventing school closures, and setting up public health infrastructure for psychological assistance.

Received: 25 Jun 2025 – Discussion started: 01 Jul 2025

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Thi Dieu My Pham, Paul Hudson, Annegret H. Thieken, and Philip Bubeck

Status: final response (author comments only)

RC1:
'Comment on egusphere-2025-3021', Anonymous Referee #1, 14 Oct 2025
Thank you for offering an opportunity to review a manuscript that investigated the compound impact of COVID-19 and flood on the mental health of a flood-prone area in Vietnam. The manuscript is well-written and structured, with methodological integrity. However, there are some queries the authors need to address.
Introduction
In page 2, line 55, the statement ‘while the flood …… and under-evaluated’ and the following references are misleading, as the authors cited a paper prior to the COVID-19. It would be a good choice if the authors cite Ogunbode et al. (2019) after ‘While the flood impacts on mental health are considerable and long-lasting.’

Otherwise, the Introduction section is well-written, documenting relevant articles in both global and regional contexts.
Methodology
The authors clearly documented the simultaneous occurrence of floods and COVID-19 in the selected study areas. They specifically mentioned using the K6 scale to measure distress among the residents of Hue City. Importantly, the K6 scale is designed to assess an individual's mental health, specifically measuring distress experienced over the past 30 days (see Kessler, R. C., Barker, P. R., Colpe, L. J., Epstein, J. F., Gfroerer, J. C., Hiripi, E., . . . Zaslavsky, A. M. (2003). Screening for serious mental illness in the general population. Archives of General Psychiatry, 60(2), 184–189. doi: 10.1001/archpsyc.60.2.184). The authors examined the mental health of residents in Hue City concerning incidents that occurred over two years ago. This raises a question about how they addressed the potential recall bias among participants and whether they considered individuals who may have relocated to study areas after 2022 from other parts of the country. Additionally, the authors did not specify any inclusion or exclusion criteria for the population studied.

The authors stated they interviewed 400 household heads using systematic random sampling from two communes; however, it is unclear if this sample size adequately represents the study areas.

The authors are requested to mention the reliability of K6 in their study.

The authors are requested to provide any relevant articles that support merging 'moderate' and 'severe' distress into the 'Yes' category. If they choose not to merge 'no' and 'moderate' distress into the 'no or moderate' distress category, they must provide an explanation for this decision.

The authors are requested to address or clarify the aforementioned issues in the methodology.
Citation: https://doi.org/10.5194/egusphere-2025-3021-RC1
- AC1: 'Reply on RC1', Thi Dieu My Pham, 18 Dec 2025
  
  Dear Reviewer,
  Thank you for your time and effort in reviewing the manuscript. We appreciate your positive evaluation of our paper and the comments and suggestions that will help to improve our manuscript further. We would like to address the comments below (in italics) and explain in our detailed point-by-point response how we will incorporate these changes into the revised version of our manuscript.
  Please find the attachment for our detailed response.
  Kind regards on behalf of all authors,
  Thi Dieu My Pham
  
  Citation: https://doi.org/10.5194/egusphere-2025-3021-AC1
RC2: 'Comment on egusphere-2025-3021', Anonymous Referee #2, 19 Dec 2025

The paper is well-written, presenting a clear and logical structure, which facilitates the reader's understanding.

The language is objective and well-founded, and the methodology is well-defined, with appropriate quantitative methods.

Furthermore, this topic is very relevant, especially in the context of research on multiple risks and public health. The work is interesting and useful for NHESS readers.

Below are some questions and suggestions for the authors:

ABSTRACT
An adequate abstract—please provide a statement explaining the "why" the study was conducted. I believe that explaining the "why" can demonstrate the purpose behind creating conceptual understanding.

INTRODUCTION
Lines 69-98: I suggest moving the initial part of these lines to the methodology section and another part to the results and discussion section.

CASE STUDY AREA

Line 111: Is there any information on the percentage of the country's population that has been or is currently affected by floods?
Line 122: Is it possible to cite historical extreme events that have occurred in the region over the decades? I believe this information is important for understanding the historical context and frequency of floods in the region.
Lines 144-151: I suggest moving this paragraph closer to Figure 1. Are the populations of these two communities representative of the population of Hue City?

METHODS

Line 154: Please briefly explain the tool and include a link to access it.
Was the collective memory of the community taken into consideration, given that the interviews were conducted years after COVID-19? How might this introduce bias into the respondents' answers? Do the authors consider this factor a limitation of the method?
(Suggested reading for concepts and discussion: https://doi.org/10.1111/jfr3.12679 ; doi.org/10.1002/2017WR022036; https://doi.org/10.3986/AGS49107).
I congratulate the authors on their excellent paper.

Citation: https://doi.org/10.5194/egusphere-2025-3021-RC2

Thi Dieu My Pham, Paul Hudson, Annegret H. Thieken, and Philip Bubeck

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Short summary

Experiencing severe flooding and COVID-19 together adversely affects mental health. A 2020 survey in Vietnam found that 20 % of participants experienced mental distress, whereas 80 % did not. Flood risk factors include livelihood difficulties, seeing dead human bodies, and being rescued; COVID-19 stressors relate to individual health impacts and interrupted education. These findings highlight the need to address health risks from multiple sources and provide more support for at-risk communities.


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