BACKGROUND:The implementation of COVID-19 vaccination among older persons at nursing homes has lowered the infection-associated mortality considerably, but emerging virus variants and decline in vaccine-induced immunity over time necessitate examination of future booster dosing strategies. The overall aim of this study was to assess vaccine protection against COVID-19 mortality in relation to time elapsed since the last booster dose. METHODS:All older persons living in nursing homes in Sweden at any time point December 27th, 2020 - December 4th, 2023 were included. For each case (5256 COVID-19 and 85,745 all-cause deaths), up to 10 controls were sampled randomly from this population, matched with respect to birth year, sex and county. The matched case-control sets were analyzed for vaccination history with conditional logistic regression, with further adjustment for co-morbidties and prior SARS-CoV-2 infection. FINDINGS:Vaccination status (unvaccinated vs. vaccinated), ≥ 90 days since last vaccine dose, a co-morbidity score ≥ 2, and no previous SARS-CoV-2 infection were associated with death occurring within 30 days of a positive test. The odds ratio (OR) for COVID-19 death was 2.4 (95 % confidende interval [CI] 1.8-3.2) when contrasting at least 365 days with less than 90 days since the last vaccine dose. INTERPRETATION:Waning vaccine protection was observed already 90 days after the last vaccine dose among older people living in nursing homes. The reported ORs imply that more than one third of all COVID-19 deaths could in the investigated setting have been possible to prevent by more frequent vaccine boosting during 2022-2023.

BACKGROUND:In May 2023, the World Health Organization declared COVID-19 no longer a public health emergency. Despite successful vaccination campaigns, vaccines provide limited protection against transmission. Since general testing has been abandoned in most countries, alternative population surveillance methods to assess SARS-CoV-2 exposure are needed. METHODS:N-antigen is a protein of the SARS-CoV-2 virus that is not present in the vaccines and hence may be a useful serological marker of infection. This study evaluated N-antigen antibodies as a marker of SARS-CoV-2 exposure in a vaccinated Swedish cohort. Serum samples were collected and analysed for N-antigen antibodies using the mesoscale system. Nonlinear mixed-effects model accounting for multiple measurements per individual was used to estimate the half-life of N-antigen antibodies. RESULTS:A total of 3,202 participants (median age 31 years) were recruited from April 2021 to February 2022 from four vaccination centres in Skåne, Sweden. A total of 2,999 participants had at least one valid N-antigen antibody measurement. The estimated half-life of N-antigen antibodies was 59 days (95% CI: 55-64 days). The estimated 95% range of halves-lives were from 24 to 174 days. The repeated measurements of N-antigen antibody levels could accurately detect SARS-CoV-2 infection. A twofold increase had a sensitivity of 91%, whereas a 16-fold increase had a specificity of 91%, respectively. The area under the curve (AUC) for predicting infection was 0.88 [95% C.I. 0.86-0.90]. CONCLUSION:Repeated monitoring of N-antigen antibody levels may be a valuable tool for assessing SARS-CoV-2 exposure and thus aid in monitoring transmission thereby helping in guiding vaccination strategies.

ObjectivesBetter understanding of societal factors associated with COVID-19 vaccination can have important implications for public health policy to increase uptake.MethodsThis study investigated sociodemographic determinants of COVID-19 vaccine uptake with ≥2 doses vs 0 doses, and ≥3 doses vs 2 doses, among adults (≥18 years) in a general population from Sweden followed from 27 December 2020 (n=1 064 548 at the present cross-section—12 June 12 2022). Associations between individual-level and area-level sociodemographic factors and vaccine uptake were modelled with logistic regression, with average marginal effects and estimated proportion vaccinated subsequently estimated.ResultsBeing vaccinated with ≥2 doses vs 0 doses was positively associated with education (tertiary vs primary, OR 1.5, 95% CI 1.3 to 1.7), household disposable income (Q5 vs Q1, OR 2.3; 95% CI 1.9 to 2.7), comorbidities (≥2 doses vs none, OR 1.9, 95% CI 1.8 to 1.9) and residential area type (affluent socioeconomic conditions vs poor, OR 2.0, 95% CI 1.6 to 2.4). Whereas, being born outside Sweden was associated with a lower uptake (low and middle-income countries vs Swedish born, OR 0.6, 95% CI 0.5 to 0.7). The associations were generally similar when comparing booster vs remaining on only two doses. From these ORs, there were consistent differences in the estimated proportion vaccinated both for ≥2 doses and booster vaccination. Absolute changes in percentage vaccinated between affluent and poor areas were largely similar across individual country of birth, income and education, both for at least two doses and for the booster doses.ConclusionsCOVID-19 vaccine uptake was associated with higher sociodemographic classifications both at the individual level and area level. The predicted proportion vaccinated increased with more affluent socioeconomic conditions and concurrent increases in individual household income were the strongest indicators. This sociodemographic selection showed consistency with respect to entering (obtaining ≥2 doses) and remaining (obtaining at least one booster dose) in the vaccination programme.

Objectives:We evaluated the protection afforded by SARS-CoV-2 infection-induced immunity against reinfection among working-age vaccinated individuals during a calendar period from June to December 2022 when Omicron BA.5 was the dominating subvariant in Scania County, Sweden.Methods:The study cohort (n = 71,592) mainly consisted of health care workers. We analyzed 4144 infected cases during the Omicron BA.5 dominance and 41,440 sex- and age-matched controls with conditional logistic regression.Results:The average protection against reinfection was marginal (16%, 95% confidence interval [CI] 7-23%) during the study period but substantially higher for recent infections. Recent infection (3-6 months) with Omicron BA.2 and BA.5 offered strong protection (86%, 95% CI 68-94% and 78%, 95% CI 69-84%), whereas more distant infection (6-12 months) with Omicron BA.1, BA.2, and the variants before Omicron offered marginal or no protection.Conclusions:These findings suggest that infection-induced immunity contributes to short-term population protection against infection with the subvariant BA.5 among working-age vaccinated individuals but wanes considerably with time, independent of the virus variant.

We evaluated the protection afforded by SARS-CoV-2 natural infection against reinfection among vaccinated during a calendar period from June to August 2022 when Omicron BA.5 was the dominating subvariant in Scania county, Sweden. We formed a study cohort (n = 71 592) mainly consisting of health care workers by restricting to people 18-64 years old who received their first vaccine dose relatively early (24 April 2021 or sooner). We used continuous density case-control 1:10 sampling matched for sex and age within the study cohort, and thereby obtained 1 114 cases during Omicron BA.5 dominance and 11 140 controls who were analysed with conditional logistic regression. Limited protection against reinfection was suggested from prior infection of virus variants before Omicron (11%, 95% confidence interval [CI] −10 to 28%]. By contrast, prior Omicron infection offered clear protection (65%, 95% CI 56-73%). For the Omicron BA.2 subvariant, stronger protection was suggested during early (85%, 95% CI 75-91%) than later BA.5 dominance (66%, 95% CI 48-78%). Lower protection was observed from the previous BA.1 subvariant (30%; 95% CI −4 to 53%). These findings suggest that natural infection from the Omicron subvariants contributes to short-term population protection against reinfection with the subvariant BA.5 among vaccinated, but wanes considerably 5-6 months after infection.### Competing Interest StatementThe authors have declared no competing interest.### Funding StatementThis study was supported by Swedish Research Council (VR; grant numbers 2019-00198 and 2021-04665), Swedish Innovation Agency (Vinnova; grant number 2021-02648) and by internal grants for thematic collaboration initiatives at Lund University held by JB and MI. FK is supported by grants from the Swedish Research Council and Governmental Funds for Clinical Research (ALF), and CB is supported by Swedish Research Council for Health, Working life and Welfare (Forte; grant number 2020-00962). The funders played no role in the design of the study, data collection or analysis, decision to publish, or preparation of the manuscript.### Author DeclarationsI confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained.YesThe details of the IRB/oversight body that provided approval or exemption for the research described are given below:Ethical approval was obtained from the Swedish Ethical Review Authority (2021-00059).I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals.YesI understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance).YesI have followed all appropriate research reporting guidelines and uploaded the relevant EQUATOR Network research reporting checklist(s) and other pertinent material as supplementary files, if applicable.YesAll data produced in the present study are available upon reasonable request to the authors, but would generally require a new ethical approval.

Objectives: To study the impact of non-mandatory, age-specific social distancing recommendations for older adults (70+ years) in Sweden on isolation behaviors and disease outcomes during the first wave of the COVID-19 pandemic. Methods: Our study relies on self-reported isolation data from COVID Symptom Study Sweden (n = 96,053) and national register data on COVID-19 hospitalizations, deaths, and confirmed cases. We use a regression discontinuity design to account for confounding factors, exploiting the fact that exposure to the recommendation was a discontinuous function of age. Results: By comparing individuals just above to those just below the age limit for the policy, our analyses revealed a sharp drop in the weekly number of visits to crowded places at the 70-year-threshold (-13%). Severe COVID-19 cases (hospitalizations or deaths) also dropped abruptly by 16% at the 70-year-threshold. Our data suggest that the age-specific recommendations prevented approximately 1,800 to 2,700 severe COVID-19 cases, depending on model specification. Conclusion: The non-mandatory, age-specific recommendations helped control the COVID-19 pandemic in Sweden.

Objectives The credit market has expanded rapidly, increasing the risk of over-indebtedness among those who lack secure employment or adequate income, an issue of concern in the COVID-19 aftermath. We investigated the role of over-indebtedness for developing poor mental health, and whether this impact is modified by age, gender, educational level or being in precarious employment.Methods This is a cohort study using data from the Swedish Scania Public Health Cohort, based on individuals randomly selected from the general adult population in Scania, southern Sweden, initiated in 1999/2000 (response rate 58%) with follow-ups in 2005 and 2010. Over-indebtedness was assessed by combining information on cash margin and difficulty in paying household bills. Mental health was assessed by General Health Questionnaire-12. Those with poor mental health at baseline were excluded, and the analyses were further restricted to vocationally active individuals with complete data on main variables, resulting in 1256 men and 1539 women.Results Over-indebtedness was more common among women, among persons with a low educational level, born abroad and with a precarious employment at baseline. The age-adjusted incidence rate ratio (IRR) for poor mental health in 2010 among individuals exposed to over-indebtedness in 1999/2000 or 2005 was 2.2 (95% CI 1.7 to 2.8). Adjusting for educational level, country of origin and precarious employment in 1999/2000 or 2005, yielded an IRR of 2.0 (95% CI 1.6 to 2.6). An interaction analysis indicated that a high level of education may act synergistically with over-indebtedness, regarding poor mental health among men.Conclusions Over-indebtedness was related to unfavourable societal power relations, regarding social class, gender and foreign birth. Precarious employment was independently linked to poor mental health and may also mediate the effect by over-indebtedness. The COVID-19 pandemic might entail increased over-indebtedness, which should be acknowledged in policies aiming at buffering social effects of the pandemic.

We compared vaccine effectiveness (VE) against severe COVID-19 during calendar periods from December 2021 to March 2022 when Omicron BA.1 and BA.2, respectively, were the dominating virus variants in Scania county, Sweden. We used continuous density case-control sampling matched for sex and age, and with further adjustment for differences in comorbidities and prior infection. VE remained relatively stable after the transition from BA.1 to BA.2 among people with at least three doses but decreased markedly among those with only two doses. Protection from prior infection was also lower after the transition to BA.2. These findings suggest that booster vaccination is needed to maintain sufficient protection against severe COVID-19.

The risk of severe COVID-19 disease requiring hospitalization with extensive oxygen supply was compared among infected cases during two calendar periods when Delta and Omicron, respectively, were the dominating virus variants in Scania county, Sweden. Adjustments were made for differences among cases in comorbidities, prior infection, vaccination status, age and sex. Markedly lower risks were observed from Omicron among the vaccinated in the present study. The risk of severe disease was also lower for unvaccinated during Omicron than during Delta, but remained high among older people and middle-aged males with comorbidities. Efforts to increase vaccination uptake across countries, populations and subgroups should thus remain a public health priority.

We compared the risk of severe COVID-19 during two periods 2021 and 2022 when Delta and Omicron, respectively, were the dominating virus variants in Scania county, Sweden. We adjusted for differences in sex, age, comorbidities, prior infection and vaccination. Risk of severe disease from Omicron was markedly lower among vaccinated cases. It was also lower among the unvaccinated but remained high (> 5%) for older people and middle-aged men with two or more comorbidities. Efforts to increase vaccination uptake should continue.

We compared vaccine effectiveness against severe COVID-19 between December 2021 and March 2022 when Omicron BA.1 and BA.2 were the dominating SARS-CoV-2 variants in Scania county, Sweden. Effectiveness remained above 80% after the transition from BA.1 to BA.2 among people with at least three vaccine doses but the point estimate decreased markedly to 54% among those with only two doses. Protection from prior infection was also lower after the transition to BA.2. Booster vaccination seems necessary to maintain sufficient protection.

Abstract The extensive register infrastructure available for coronavirus disease 2019 surveillance in Scania county, Sweden, makes it possible to classify individual cases with respect to hospitalisation and disease severity, stratify on time since last dose and demographic factors, account for prior infection and extract data for population controls automatically. In the present study, we developed a case–control sampling design to surveil vaccine effectiveness (VE) in this ethnically and socioeconomically diverse population with more than 1.3 million inhabitants. The first surveillance results show that estimated VE against hospitalisation and severe disease 0–3 months after the last dose remained stable during the study period, but waned markedly 6 months after the last dose in persons aged 65 years or over.

Background Vaccine effectiveness against COVID-19 needs to be assessed in diverse real-world population settings. Methods A cohort study of 805 741 residents in Scania county, Southern Sweden, aged 18-64 years, of whom 26 587 received at least one dose of the BNT162b2 vaccine. Incidence rates of COVID-19 were estimated in sex- and age-adjusted analysis and stratified in two-week periods with substantial community spread of the disease. Results The estimated vaccine effectiveness in preventing infection >7 days after second dose was 86% (95% CI 72-94%) but only 42% (95% CI 14-63%) >14 days after a single dose. No difference in vaccine effectiveness was observed between females and males. Having a prior positive test was associated with 91% (95% CI 85 to 94%) effectiveness against new infection among the unvaccinated. Conclusion A satisfactory effectiveness of BNT162b2 after the second dose was suggested, but with possibly substantially lower effect before the second dose.

Aims: To investigate potential differences between participants and dropouts in the 2005 follow-up of the Scania Public Health Cohort Study regarding the prevalence of commonly studied health determinants and whether these factors had differential associations with three health outcomes: all-cause mortality and purchase of prescribed cardiovascular or psychotropic drugs during a 10-year follow-up period. Methods: The Scania Public Health Cohort was initiated in 1999/2000, with randomly invited participants aged 18–80 years from the general population (58% participation). Questionnaire data from 10,462 participants and 2576 dropouts in the 2005 follow-up (80% participation) were linked to public registers on mortality and purchase of prescribed drugs. Results: Age, male gender, being born abroad, low educational level, low self-rated mental and general health and daily smoking were all related to dropping out. The 10-year mortality was higher among dropouts (13.4% versus 11.9%; age-adjusted hazard ratio 1.6, 95% confidence interval: 1.4–1.8). In 13 out of 18 analyses, similar associations between health determinants and outcomes were found across participants and dropouts. However, being born outside of Sweden was associated with higher risks for all three poor health outcomes among participants, but not so among dropouts. Conclusions: Despite selective participation at follow-up, there was little evidence of selection bias, insofar as estimated associations were generally similar across participants, dropouts and the whole cohort. This finding is important for the assessment of the validity of prospective findings from this cohort and similar ones, where the loss of individuals at consecutive follow-ups of exposure is non-negligible.

AbstractThe aim of this cohort study was to investigate sociodemographic determinants of COVID-19 vaccine uptake in the 70+ age group in Skåne county, Sweden (n = 216 243 at baseline). Uptake of the first dose was high (91.9%) overall, but markedly lower (75.3%) among persons born outside the Nordic countries. Vaccine uptake was generally satisfactory among native Swedes also in areas with lower socioeconomic status, but dropped substantially among non-Nordic born in those areas. The identified clusters of unvaccinated older people, mainly representing ethnic minorities in disadvantaged areas, warrants intensified efforts regarding tailored communication, easier vaccine access and local engagement.Key pointsCOVID-19 vaccine uptake in the 70+ age group in Skåne county, Sweden, was high (91.9%) overall, but markedly lower (75.3%) within the group born outside the Nordic countriesInverse associations between indicators of neighbourhood deprivation and vaccine uptake were observed, which lowered the uptake among persons born outside the Nordic countries furtherThe identified clusters of unvaccinated older people, mainly representing ethnic minorities in disadvantaged areas, warrants intensified efforts regarding tailored communication, easier vaccine access and local engagement

Precarious employment has been associated with poor mental health. Moreover, increasing labour market precariousness may cause individuals to feel 'locked-in', in non-desired workplaces or occupations, out of fear of not finding a new employment. This could be experienced as a 'loss of control', with similar negative health consequences. It is plausible that the extent to which being in a non-desired occupation (NDO) or being in precarious employment (PE) has a negative impact on mental health differs according to age group. We tested this hypothesis using data from 2331 persons, 18-34, 35-44, and 45-54 years old, who answered questionnaires in 1999/2000, 2005, and 2010. Incidence rate ratios (IRR) were calculated for poor mental health (GHQ-12) in 2010, after exposure to NDO and PE in 1999/2000 or 2005. NDO and PE were more common in the youngest age group, and they were both associated with poor mental health. In the middle age group the impact of NDO was null, while in contrast the IRR for PE was 1.7 (95% CI: 1.3-2.3) after full adjustment. The pattern was completely the opposite in the oldest age group (adjusted IRR for NDO 1.6 (1.1-2.4) and for PE 0.9 (0.6-1.4)). The population attributable fraction of poor mental health was 14.2% and 11.6%, respectively, for NDO in the youngest and oldest age group, and 17.2% for PE in the middle age group. While the consequences of PE have been widely discussed, those of NDO have not received attention. Interventions aimed at adapting work situations for older individuals and facilitating conditions of job change in such a way as to avoid risking unemployment or precarious employment situations may lead to improved mental health in this age group.

The globalisation of the economy and the labour markets has resulted in a growing proportion of individuals who find themselves in a precarious labour market situation, especially among the young. This pertains also to the Nordic countries, despite their characterisation as well developed welfare states with active labour market policies. This should be viewed against the background of a number of studies, which have shown that several aspects of precarious employment are detrimental to mental health. However, longitudinal studies from the Nordic region that examine the impact of precarious labour market conditions on mental health in young individuals are currently lacking. The present study aims to examine this impact in a general cohort of Swedish young people.

The aim of this study was to investigate whether job strain, psychological demands, and decision latitude are independent determinants of disability pension rates over a 12-year follow-up period.

Previous studies have found insomnia and long sleep duration to be independently associated with subsequent disability pension (DP). However, the issue of a possible gender-based pattern in this context has received little attention.

This study of 17,443 childbearing women, investigated the relationship between hospital admissions 5 years prior to index birth, type of mental disorders and risk factors for mode of delivery. Hospital based electronic perinatal medical records between 2001 and 2006, were linked with the Swedish National Inpatient Care Registry 1996-2006. Of all the women, 39.3% had had inpatient care prior to index birth (27.3% had had obstetric, 10.1% somatic, and 1.9% psychiatric inpatient care). Diagnoses of mental disorders at psychiatric admission (n = 333) were categorized into five groups: personality/behavioral/unspecified disorder (30.9%), affective disorders and 'suicide attempt' (28.9%), neurotic/somatoform disorders (18.9%), substance use (17.1%) and schizophrenia (4.2%). Women with history of psychiatric care were more often smokers, below age 24 and single (p < 0.001, respectively), had more markers of mental ill-health in pregnancy records (p = 0.001), compared to women without such previous care, and fewer were nulliparous (p < 0.001). The results show that women with prior psychiatric inpatient care and those with identified mental ill-health in pregnancy records, were associated with increased adjusted risks of cesarean sections. Identifying a woman's mental health status in pregnancy may predict and prevent emergency cesarean section.