Are Individuals with Substance Use Disorders at Higher Risk of SARS-CoV-2 Infection? Population-Based Registry Study in Northern Italy

Seroprevalence of SARS-CoV-2 and humoral immune responses to COVID-19 mRNA vaccines among people who use drugs - in the light of tailored mitigating strategies

BACKGROUND

During the initial wave of the COVID-19 pandemic, there was a surprisingly low incidence of SARS-CoV-2 among People Who Use Drugs (PWUD) in Oslo, Norway, despite their heightened vulnerability regarding risk of infection and severe courses of the disease.This study aims to investigate the seroprevalence of SARS-CoV-2 antibodies among PWUD, their antibody responses to relevant virus infections and COVID-19 mRNA vaccines, and their vaccination coverage compared to the general population.

METHODS

Conducted as a prospective cohort study, data was collected from residents in six institutions for homeless PWUD and users of a low-threshold clinic for opioid agonist treatment. Ninety-seven participants were recruited for SARS-CoV-2 seroprevalence analysis. Additional two participants with known positive SARS-CoV-2 test results were recruited for further analyses. Twenty-five participants completed follow-up. Data included questionnaires, nasal swabs and blood samples. Data on vaccination coverage was obtained from the National Vaccine Register. Serologic methods included detection of antibodies to relevant virus proteins, neutralizing antibodies to SARS-CoV-2, antibodies to the full-length spike protein, and receptor-binding domain from SARS-CoV-2.

RESULTS

Among PWUD, antibodies to SARS-CoV-2 were detected in 2 out of 97 samples before vaccines against SARS-CoV-2 were available, comparable to a 2.8% frequency in population-based screening. Levels of serum antibodies to seasonal coronaviruses and Epstein-Barr-Virus (EBV) in PWUD were similar to population-based levels. After the second vaccine dose, binding and neutralizing antibody levels to SARS-CoV-2 in PWUD were comparable to controls. Eighty-four of PWUD received at least one dose of COVID-19 mRNA vaccine, compared to 89% in the general population.

CONCLUSION

Results indicate that PWUD did not exhibit increased SARS-CoV-2 seroprevalence or elevated serum antibodies to seasonal coronaviruses and EBV. Moreover, vaccine responses in PWUD were comparable to controls, suggesting that vaccination is effective in conferring protection against SARS-CoV-2 also in this population.

Incidence of SARS-CoV-2 and all-cause mortality in persons with co-occurring substance use disorder and mental illness during the pandemic: a Norwegian cohort study

PURPOSE

Most people were affected by the COVID-19 pandemic. Persons with co-occurring substance use disorder (SUD) and mental illness (MI) are already a marginalized group, with above average mortality. Thus, the study aim was to investigate SARS-CoV-2 incidence and mortality among persons with SUD/MI during the first two years of the pandemic.

METHODS

This historical cohort study merged data from the Norwegian Patient Register, the Norwegian Surveillance System for Communicable Diseases and census data from Statistics Norway. We calculated crude mortality rates for persons with SUD and mild/moderate vs. severe MI and compared them to persons with physical illnesses or healthy controls. The incidence rate ratios for SARS-CoV-2 infection and mortality were estimated using Poisson regression models.

RESULTS

Compared to healthy controls, the SARS-Cov-2-infection rate was marginally lower in persons with SUD and mild/moderate MI (IRR,1.19 [95%CI,1.09-1.30]) as in persons with physical illness (IRR,1.35 [95%CI, 1.23-1.47]), whereas persons with SUD and severe MI showed a lower rate compared to healthy controls. Crude mortality rates for persons with SUD/MI were substantially higher and increased much more during the pandemic than for persons with physical illnesses or healthy controls. The IRR for mortality in persons with SUD and mild/moderate MI was 10.61 (95%CI,7.19-15.67) and 11.44 (95%CI,7.50-17.45) for SUD and severe MI, compared to 5.03 (3.34-7.57]) for persons with physical illnesses only.

CONCLUSION

The analysis showed excess mortality during COVID-19-pandemic for SUD/MI, but without higher SARS-CoV-2 infection rates in this group. Consequently, excess mortality among persons with SUD/MI was not due to SARS-CoV-2 infection.

Unintended Consequences of COVID-19 Non-Pharmaceutical Interventions (NPIs) for Population Health and Health Inequalities

Since the start of the COVID-19 pandemic in early 2020, governments around the world have adopted an array of measures intended to control the transmission of the SARS-CoV-2 virus, using both pharmaceutical and non-pharmaceutical interventions (NPIs). NPIs are public health interventions that do not rely on vaccines or medicines and include policies such as lockdowns, stay-at-home orders, school closures, and travel restrictions. Although the intention was to slow viral transmission, emerging research indicates that these NPIs have also had unintended consequences for other aspects of public health. Hence, we conducted a narrative review of studies investigating these unintended consequences of NPIs, with a particular emphasis on mental health and on lifestyle risk factors for non-communicable diseases (NCD): physical activity (PA), overweight and obesity, alcohol consumption, and tobacco smoking. We reviewed the scientific literature using combinations of search terms such as 'COVID-19', 'pandemic', 'lockdowns', 'mental health', 'physical activity', and 'obesity'. NPIs were found to have considerable adverse consequences for mental health, physical activity, and overweight and obesity. The impacts on alcohol and tobacco consumption varied greatly within and between studies. The variability in consequences for different groups implies increased health inequalities by age, sex/gender, socioeconomic status, pre-existing lifestyle, and place of residence. In conclusion, a proper assessment of the use of NPIs in attempts to control the spread of the pandemic should be weighed against the potential adverse impacts on other aspects of public health. Our findings should also be of relevance for future pandemic preparedness and pandemic response teams.