Why were so few randomized trials of public health and social measures conducted during the COVID-19 pandemic? The Norwegian experience.

BACKGROUND: Few randomized trials of public health and social measures were carried out during the COVID-19 pandemic. We report on the major barriers we faced when we tried to run such trials. METHODS: We reviewed all randomized trials proposed and initiated by the Centre for Epidemic Interventions Research in Norway during the COVID-19 pandemic. RESULTS: Of the 18 proposed trials, 11 trials were not implemented. One of the key legal and ethical barriers to conducting the trials was the Norwegian Health Research Act, which demands informed consent from all participants who are exposed to an intervention. A lack of sufficient political support was also a challenge, as was unpredictability, due to shifting disease incidence and changing recommendations from the authorities. CONCLUSION: Strengthening the evidence base for public health and social measures in pandemics will require political and public understanding and support and a legal framework that allows for the conduct of such trials.

Personal protective effect of wearing surgical face masks in public spaces on self-reported respiratory symptoms in adults: pragmatic randomised superiority trial.

OBJECTIVE: To evaluate the personal protective effects of wearing versus not wearing surgical face masks in public spaces on self-reported respiratory symptoms over a 14 day period. DESIGN: Pragmatic randomised superiority trial. SETTING: Norway. PARTICIPANTS: 4647 adults aged ≥18 years: 2371 were assigned to the intervention arm and 2276 to the control arm. INTERVENTIONS: Participants in the intervention arm were assigned to wear a surgical face mask in public spaces (eg, shopping centres, streets, public transport) over a 14 day period (mask wearing at home or work was not mentioned). Participants in the control arm were assigned to not wear a surgical face mask in public places. MAIN OUTCOME MEASURES: The primary outcome was self-reported respiratory symptoms consistent with a respiratory infection. Secondary outcomes included self-reported and registered covid-19 infection. RESULTS: Between 10 February 2023 and 27 April 2023, 4647 participants were randomised of whom 4575 (2788 women (60.9%); mean age 51.0 (standard deviation 15.0) years) were included in the intention-to-treat analysis: 2313 (50.6%) in the intervention arm and 2262 (49.4%) in the control arm. 163 events (8.9%) of self-reported symptoms consistent with respiratory infection were reported in the intervention arm and 239 (12.2%) in the control arm. The marginal odds ratio was 0.71 (95% confidence interval (CI) 0.58 to 0.87; P=0.001) favouring the face mask intervention. The absolute risk difference was -3.2% (95% CI -5.2% to -1.3%; P<0.001). No statistically significant effect was found on self- reported (marginal odds ratio 1.07, 95% CI 0.58 to 1.98; P=0.82) or registered covid-19 infection (effect estimate and 95% CI not estimable owing to lack of events in the intervention arm). CONCLUSION: Wearing a surgical face mask in public spaces over 14 days reduces the risk of self-reported symptoms consistent with a respiratory infection, compared with not wearing a surgical face mask. TRIAL REGISTRATION: ClinicalTrials.gov NCT05690516.

Association between face mask use and risk of SARS-CoV-2 infection: Cross-sectional study.

We examined the association between face masks and risk of infection with SARS-CoV-2 using cross-sectional data from 3,209 participants in a randomized trial exploring the effectiveness of glasses in reducing the risk of SARS-CoV-2 infection. Face mask use was based on participants' response to the end-of-follow-up survey. We found that the incidence of self-reported COVID-19 was 33% (aRR 1.33; 95% CI 1.03-1.72) higher in those wearing face masks often or sometimes, and 40% (aRR 1.40; 95% CI 1.08-1.82) higher in those wearing face masks almost always or always, compared to participants who reported wearing face masks never or almost never. We believe the observed increase in the incidence of infection associated with wearing a face mask is likely due to unobservable and hence nonadjustable differences between those wearing and not wearing a mask. Observational studies reporting on the relationship between face mask use and risk of respiratory infections should be interpreted cautiously, and more randomized trials are needed.

Migrant background and the impact of the COVID-19 pandemic on mental healthcare consultations among children and adolescents in Norway: a nationwide registry study.

BACKGROUND: Despite concern about migrant children's mental health and their access to mental healthcare services during the COVID-19 pandemic, this topic has attracted little research attention. This study aimed to examine the impact of the COVID-19 pandemic on the use primary and specialist healthcare services for mental health problems among children and adolescents with migrant background. METHODS: Using event study models, we investigated the impact of lockdown and subsequent COVID-19 infection control measures on children's health service use for mental health problems according to migrant background. Drawing on reimbursement data from Norwegian public healthcare providers we observe consultations in a pre-pandemic (2017-2019) and pandemic cohort (2019-2021) in primary and specialised care. RESULTS: The pre-pandemic cohort included 77 324 migrants, 78 406 descendants of migrants and 746 917 non-migrants and the pandemic cohort included 76 830 migrants, 88 331 descendants and 732 609 non-migrants (age 6-19). The full cohorts were observed for mental healthcare use in primary care while a subsample (age 6-16) was observed for health care use in specialist care. Lockdown resulted in a dip in consultation volumes for mental disorders for all children, but this dip was relatively larger and more persistent for children with migrant background. After lockdown, consultation volumes rose more for non-migrant children than for children with migrant background. Consultations in primary healthcare peaked during January to April 2021 for non-migrants and descendants of migrants, but not for migrants (4%, 95% CI -4 to 11). In specialist care during the same period, consultations dropped by 11% for migrants (95% CI -21 to -1). By October 2021, all mental health consultations in specialist care were up with 8% for non-migrants (95% CI 0 to 15), and down with -18% for migrants and -2% for descendants (95% CIs -31 to -5 and -14 to 10). Migrant males experienced the largest reduction in consultations. CONCLUSIONS: Changes in consultation volumes among children with migrant background after lockdown were not as pronounced as for non-migrants, and at times actually decreased. This suggests that an increase in barriers to care emerged during the pandemic for children with a migrant background.

GP phone calls to improve COVID-19 vaccine uptake among patients at increased risk of severe COVID-19: a randomised trial.

BACKGROUND: English media have reported that many unvaccinated individuals took the COVID-19 vaccine after receiving a phone call from their GP. AIM: To determine whether phone calls from GPs to unvaccinated patients at increased risk of severe COVID-19 improves uptake of the COVID-19 vaccine. DESIGN & SETTING: Randomised trial where 202 participants were allocated to receive a phone call from their GP, and 452 participants were allocated to not get the call. Twenty-five GPs at 11 medical centres in Norway took part. The post-trial focus group discussion was with five GPs. METHOD: Participants were sourced from the GP electronic medical record system, which communicates with the Norwegian Immunisation Registry and can generate a list of the GPs' unvaccinated patients at increased risk of severe COVID-19. RESULTS: The GPs managed to speak over the phone with 154 (76%) patients allocated to receiving a phone call. At follow-up (average 7.5 weeks), 8.9% in the intervention group and 5.3% in the control group had been vaccinated (odds ratio [OR] 1.72; 95% confidence interval [CI] = 0.90 to 3.28). Findings from the focus group discussion suggested the timing of the intervention as a likely key reason for its limited success. CONCLUSION: An increase in the proportion of patients who took the COVID-19 vaccine in the intervention group was observed, but the difference was smaller than anticipated, and may be a chance finding. The effect of this type of intervention will likely vary across contexts and may have proved more effective if a larger proportion of the population were unvaccinated.

Transmission of severe acute respiratory coronavirus virus 2 (SARS-CoV-2) between hospital workers and members of their household: Nationwide, registry-based, cohort study from Norway.

BACKGROUND: Understanding and limiting infection in healthcare workers (HCWs) and subsequent transmission to their families is always important and has been underscored during the COVID-19 pandemic. Except in specific and local settings, little is known about the extent of such transmissions at the national level. OBJECTIVE: To describe SARS-CoV-2 infection in HCWs and to estimate the risk of HCWs transmitting COVID-19 to their household members, including calculating the secondary attack rate to household members and estimating the risk for hospital workers to contract COVID-19 at home. METHODS: Using individual-level data on all HCWs employed in Norwegian hospitals and their household members, we identified (1) the number of HCWs who tested positive for SARS-CoV-2 between August 2020 and September 2021 and the proportion of those who were index cases in their own household and (2) the number of HCWs who were secondary cases in their own households. RESULTS: During this period, ∼3,005 (2,6%) hospital workers acquired COVID-19. Almost half of all hospital workers with confirmed COVID-19 were likely index cases in their own households. When the index case in a family was an HCW, the secondary attack rate was 24.8%. At least 17.8% of all confirmed COVID-19 cases among hospital workers were acquired in the household. CONCLUSIONS: Our results suggest not only that many HCWs are infected with SARS-CoV-2 in their households but also that infected HCWs constitute a serious infection risk to members of the HCW's household.

Effect of Wearing Glasses on Risk of Infection With SARS-CoV-2 in the Community: A Randomized Clinical Trial.

Importance: Observational studies have reported an association between the use of eye protection and reduced risk of infection with SARS-CoV-2 and other respiratory viruses, but, as with most infection control measures, no randomized clinical trials have been conducted. Objectives: To evaluate the effectiveness of wearing glasses in public as protection against being infected with SARS-CoV-2 and other respiratory viruses. Design, Setting, and Participants: A randomized clinical trial was conducted in Norway from February 2 to April 24, 2022; all adult members of the public who did not regularly wear glasses, had no symptoms of COVID-19, and did not have COVID-19 in the last 6 weeks were eligible. Intervention: Wearing glasses (eg, sunglasses) when close to others in public spaces for 2 weeks. Main Outcomes and Measures: The primary outcome was a positive COVID-19 test result reported to the Norwegian Surveillance System for Communicable Diseases. Secondary outcomes included a positive COVID-19 test result and respiratory infection based on self-report. All analyses adhered to the intention-to-treat principle. Results: A total of 3717 adults (2439 women [65.6%]; mean [SD] age, 46.9 [15.1] years) were randomized. All were identified and followed up in the registries, and 3231 (86.9%) responded to the end of study questionnaire. The proportions with a reported positive COVID-19 test result in the national registry were 3.7% (68 of 1852) in the intervention group and 3.5% (65 of 1865) in the control group (absolute risk difference, 0.2%; 95% CI, -1.0% to 1.4%; relative risk, 1.10; 95% CI, 0.75-1.50). The proportions with a positive COVID-19 test result based on self-report were 9.6% (177 of 1852) in the intervention group and 11.5% (214 of 1865) in the control group (absolute risk difference, -1.9%; 95% CI, -3.9% to 0.1%; relative risk, 0.83; 95% CI, 0.69-1.00). The risk of respiratory infections based on self-reported symptoms was lower in the intervention group (30.8% [571 of 1852]) than in the control group (34.1% [636 of 1865]; absolute risk difference, -3.3%; 95% CI, -6.3% to -0.3%; relative risk, 0.90; 95% CI, 0.82-0.99). Conclusions and Relevance: In this randomized clinical trial, wearing glasses in the community was not protective regarding the primary outcome of a reported positive COVID-19 test. However, results were limited by a small sample size and other issues. Glasses may be worth considering as one component in infection control, pending further studies. Trial Registration: ClinicalTrials.gov Identifier: NCT05217797.

No evidence for added value of introducing mandatory COVID-19 testing for international travellers entering Norway with a valid EU digital COVID certificate.

BACKGROUND: As a response to the emergence of the new Omicron SARS-CoV-2 variant, on December 3, 2021, mandatory testing after entry to Norway was extended to include international travellers with a valid COVID-19 certificate. We aim to validate if mandatory testing upon arrival increased the proportion of travellers confirmed with a positive COVID-19 test after entry. METHODS: We used individual level data on registered travellers linked with data on COVID-19 testing and confirmed COVID-19 cases. The proportions of confirmed cases among international travellers before and after the requirement were introduced was analysed with an interrupted times series design. RESULTS: The proportion of travellers with an EU COVID-19 certificate tested at an official test station increased from 3% to 43% after mandatory testing was introduced. However, the proportion of all travellers confirmed with COVID-19 rose only marginally with 0.14 percentage point directly after the intervention (p-value .06). The results are limited by the absence of data on antigen tests taken by the traveller at home and missing data from travellers without a valid Norwegian ID. CONCLUSIONS: Our findings suggest that the benefit of mandatory testing of all international travellers to Norway was marginal in the period directly after the emergence of the omicron variant. This result must be understood in the context of free of charge testing at official test centres, a government recommendation on a low threshold to test when experiencing symptoms in addition to limited surveillance of the compliance of the test after arrival requirement.

The Evaluation of a Social Media Campaign to Increase COVID-19 Testing in Migrant Groups: Cluster Randomized Trial.

BACKGROUND: A low test positivity rate is key to keeping the COVID-19 pandemic under control. Throughout the pandemic, several migrant groups in Norway have seen higher rates of confirmed COVID-19 and related hospitalizations, while test positivity has remained high in the same groups. The Norwegian government has used several platforms for communication, and targeted social media advertisements have in particular been an important part of the communication strategy to reach these groups. OBJECTIVE: In this study, we aimed to investigate whether such a targeted Facebook campaign increased the rate of COVID-19 tests performed in certain migrant groups. METHODS: We randomly assigned 386 Norwegian municipalities and city districts to intervention or control groups. Individuals born in Eritrea, Iraq, Pakistan, Poland, Russia, Somalia, Syria, and Turkey residing in intervention areas were targeted with a social media campaign aiming at increasing the COVID-19 test rate. The campaign message was in a simple language and conveyed in the users' main language or in English. RESULTS: During the 2-week follow-up period, the predicted probability of having a COVID-19 test taken was 4.82% (95% CI 4.47%-5.18%) in the control group, and 5.58% (95% CI 5.20%-5.99%) in the intervention group (P=.004). CONCLUSIONS: Our targeted social media intervention led to a modest increase in test rates among certain migrant groups in Norway. TRIAL REGISTRATION: ClinicalTrials.gov NCT04866589; https://clinicaltrials.gov/ct2/show/NCT04866589.

SARS-CoV-2 infections and hospitalisations among immigrants in Norway-significance of occupation, household crowding, education, household income and medical risk: a nationwide register study.

BACKGROUND: As in other countries, the COVID-19 pandemic has affected Norway's immigrant population disproportionately, with significantly higher infection rates and hospitalisations. The reasons for this are uncertain. METHODS: Through the national emergency preparedness register, BeredtC19, we have studied laboratory-confirmed infections with SARS-CoV-2 and related hospitalisations in the entire Norwegian population, by birth-country background for the period 15 June 2020 to 31 March 2021, excluding the first wave due to limited test capacity and restrictive test criteria. Straightforward linkage of individual-level data allowed adjustment for demographics, socioeconomic factors (occupation, household crowding, education and household income), and underlying medical risk for severe COVID-19 in regression models. RESULTS: The sample comprised 5.49 million persons, of which 0.91 million were born outside of Norway, there were 82,532 confirmed cases and 3088 hospitalisations. Confirmed infections in this period (per 100,000): foreign-born 3140, Norwegian-born with foreign-born parents 4799 and Norwegian-born with Norwegian-born parent(s) 1011. Hospitalisations (per 100,000): foreign-born 147, Norwegian-born with foreign-born parents 47 and Norwegian-born with Norwegian-born parent(s) 37. The addition of socioeconomic and medical factors to the base model (age, sex, municipality of residence) attenuated excess infection rates by 12.0% and hospitalisations by 3.8% among foreign-born, and 10.9% and 46.2%, respectively, among Norwegian-born with foreign parents, compared to Norwegian-born with Norwegian-born parent(s). CONCLUSIONS: There were large differences in infection rates and hospitalisations by country background, and these do not appear to be fully explained by socioeconomic and medical factors. Our results may have implications for health policy, including the targeting of mitigation strategies.

Increased COVID-19 Testing Rates Following Combined Door-to-Door and Mobile Testing Facility Campaigns in Oslo, Norway, a Difference-in-Difference Analysis.

High testing rates limit COVID-19 transmission. Attempting to increase testing rates, Stovner District in Oslo, Norway, combined door-to-door campaigns with easy access testing facilities. We studied the intervention's impact on COVID-19 testing rates. The Stovner District administration executed three door-to-door campaigns promoting COVID-19 testing accompanied by drop-in mobile COVID-19 testing facilities in different areas at 2-week intervals. We calculated testing rates pre- and post-campaigns using data from the Norwegian emergency preparedness register for COVID-19 (Beredt C19). We applied a difference-in-difference approach using ordinary least square regression models and robust standard errors to estimate changes in COVID-19 testing rates. Door-to-door visits reached around one of three households. Intervention and comparison areas had identical testing rates before the intervention, and we observed an increase in intervention areas after the campaigns. We estimate a 43% increase in testing rates over the first three days following the door-to-door campaigns (p = 0.28), corresponding to an additional 79 (95% confidence interval, -54 to 175) people tested. Considering the shape of the time series curves and the large effect estimate, we find it highly likely that the campaigns had a substantial positive impact on COVID-19 testing rates, despite a p-value above the conventional levels for statistical significance. The results and the feasibility of the intervention suggest that it may be worth implementing in similar settings.

The Effectiveness of Free Face Mask Distribution on Use of Face Masks. A Cluster Randomised Trial in Stovner District of Oslo, Norway.

Face masks are recommended as a means of reducing the spread of COVID-19, but there are practically no studies of interventions to increase face mask use. Over three weeks, nine grocery stores in the Stovner District of Oslo were randomly selected each day to have distribution of free face masks outside their entrance. Free face mask distribution increased the proportion of customers wearing a mask by 6.0 percentage points (adjusted, 95% CI 3.5-8.5). Mean mask usage was 91.7% in the control group and 97.1% in the treatment group (pooled SD 5.3%). Practically all those who wore masks had both nose and mouth covered. We conclude that free distribution of face masks increased their use. Similar trials can be conducted within a short period of time.