Category: News

PANSOC Postdoc Maria Dunbar has just published an article in the journal Infectious Disease Modelling. The article reviews different frameworks for conceptualizing how diseases may be transmitted within populations with heterogenous subgroups, called transmission matrices. Early transmission matrices were based on theoretical approaches to population mixing, but these have been supplemented by matrices that have a more empirical basis in, for example, survey data. The paper discusses these different approaches and how common methods have changed over time.

Jessica Dimka, Ben Schneider, and Svenn-Erik Mamelund have recently published a protocol for a systematic review that analyzes evidence on the long-term mental health consequences of historical influenza pandemics. The protocol, published by the Scandinavian Journal of Public Health, is currently available in open access.

The systematic review, which is now in progress, will examine scientific literature that explores whether influenza pandemics from the late 19th century to the early 21st century produced enduring mental illness. The protocol includes a substantial review of relevant literature on the topic that may be of interest to researchers in this area.

In a paper just published in Vaccine: X, Jessica Dimka uses survey data from Oslo to study differences in vaccine uptake and COVID-19 infection between people with chronic health conditions, disabilities, and those without medical risk factors.

Governments took a wide variety of prioritization approaches for COVID-19 vaccination, with some countries or territories giving priority to a people with many types of disabilities and pre-existing medical conditions, and other entities recommending a more narrow prioritization. There is also evidence that people with disabilities are less likely to be vaccinated, either because of vaccine hesitancy or difficulty accessing vaccination sites. In a survey jointly developed by PANSOC and the Pandemic Centre at the University of Bergen, respondents were asked if they had a chronic health condition or disability, whether they planned to take the vaccine, and about disease outcomes.

Analyzing the associations between these data, Dimka found that people with chronic health conditions were more likely to be offered and to accept the vaccine, while individuals with at least one disability were more likely to report a probable COVID case (all in comparison to individuals with no medical risk factors). Reporting probable cases (rather than confirmed) suggests that individuals with disabilities may have had less access to testing or willingness to be tested. The results also indicate that further research is needed to determine potential differences between people with different types of disabilities. In terms of vaccine hesitancy, people with chronic health conditions were less likely to express hesitancy, while people who self-identified as having at least one disability were more likely to be hesitant (than people with no chronic health conditions or disabilities).

Overall, Dimka argues that people with chronic health conditions either exhibited behaviors that might be expected for a group prioritized by public health bodies, or acted in ways accordant with their possible increased risk. In contrast, people with disabilities had little difference from people without risk factors, or slightly worse outcomes in terms of vaccination.

We at PANSOC have been a co-author with other Nordic colleagues writing about the impact of COVID-19 on mortality in Norway and Sweden 2020-22.

The lead author, Per Henrik Zahl, has been interviewed about the paper in Aftenposten: Forskere mener koronatiltak kostet 133 millioner kroner for hvert sparte liv (aftenposten.no)

You can read the paper full here: Mortality in Norway and Sweden during the COVID-19 pandemic 2020 – 22: A comparative study – ScienceDirect

Background

Norway and Sweden picked two different ways to mitigate the dissemination of the SARS-CoV-2 virus. Norway introduced the strictest lockdown in Europe with strict border controls and intense virus tracking of all local outbreaks while Sweden did not. That resulted in 477 COVID-19 deaths (Norway) and 9737 (Sweden) in 2020, respectively.

Methods

Weekly number of COVID-19 related deaths and total deaths for 2020-22 were collected as well as weekly number of deaths for 2015-19 which were used as controls when calculating excess mortality. During the first 12-18 months with high rate of virus transmission in the society, excess mortality rates were used as substitute for COVID-19 deaths. When excess mortality rates later turned negative because of mortality displacement, COVID-19 deaths adjusted for bias due to overreporting were used.

esults

There were 17521 COVID-19 deaths in Sweden and 4272 in Norway in the study period. The rate ratio (RR) of COVID-19 related deaths in Sweden vs. Norway to the end of week 43, 2022, was 2.11 (95% CI 2.05-2.19). RR of COVID-19 related deaths vs. excess number of deaths were 2.5 (Sweden) and 1.3 (Norway), respectively. RR of COVID-19 deaths in Sweden vs. Norway after adjusting for mortality displacement and lockdown, was 1.35 (95% CI 1.31-1.39), corresponding to saving 2025 life in Norway. If including all deaths in 2022, RR=1.28 (95% CI 1.24-1.31).

Conclusions

Both COVID-19 related mortality and excess mortality rates are biased estimates. When adjusting for bias, mortality differences declined over time to about 30% higher mortality in Sweden after 30 months with pandemics and at the cost of 12 million € per prevented death in Norway.