The importance of sustained compliance with physical distancing during COVID-19 vaccination rollout.

BACKGROUND: Increasing vaccination coverage against SARS-CoV-2 enabled relaxation of lockdowns in many countries in Europe. As the vaccination rollouts progressed, the public health authorities were seeking recommendations on the continuation of physical distancing measures during ongoing vaccination rollouts. Compliance with these measures was declining while more transmissible virus variants have emerged. METHODS: We used a SARS-CoV-2 transmission model to investigate the feedback between compliance, infection incidence, and vaccination coverage. We quantified our findings in terms of cumulative number of new hospitalisations three and six months after the start of vaccination. RESULTS: Our results suggest that the combination of fast waning compliance in non-vaccinated individuals, low compliance in vaccinated individuals, low vaccine efficacy against infection and more transmissible virus variants may result in a higher cumulative number of new hospitalisations than in a situation without vaccination. These adverse effects can be alleviated by deploying behavioural interventions that should preferably target both vaccinated and non-vaccinated individuals. The choice of the most appropriate intervention depends on vaccination rate and vaccine efficacy against infection. CONCLUSIONS: Supplementary behavioural interventions aiming to boost compliance to physical distancing measures can improve the outcome of vaccination programmes, until vaccination coverage is sufficiently high. For optimal results, these interventions should be selected based on the vaccine efficacy against infection and expected vaccination rate. While we considered the dynamics of SARS-CoV-2, the qualitative effects of the interplay between infectious disease spread and behavior on the outcomes of a vaccination programme can be used as guidance in a future similar pandemic.

Identifying Sexually Transmitted Infection Risk Groups Based on Behavioral and Psychological Characteristics Among Heterosexuals During the COVID-19 Pandemic.

BACKGROUND: Measures to reduce coronavirus disease (COVID-19) transmission may impact sexual health. We aimed to examine the impact of COVID-19 on sexual behavior and sexually transmitted infection (STI) testing and to characterize individuals who were at high STI risk. METHODS: Dutch heterosexual males and females who participated in a cohort study in 2016 to 2018 were invited to fill out 2 questionnaires again in 2020 (age, 21-28 years). We used behavioral and psychological data from: prelockdown (September 2019 to February 2020), lockdown (March to May 2020), and postlockdown (June to August 2020). Behavior change was compared between subgroups identified with latent class analysis. RESULTS: Four latent classes were identified (n = 238). Individuals in class 1 (48% of study population) and class 2 (36%) were at low STI risk and reported mostly steady partnerships. Individuals in class 3 (9%) and class 4 (7%) reported multiple casual partners prelockdown. Class 4 was characterized by lower condom use and health goals, negative infection prevention attitudes, and higher impulsiveness compared with class 3. Furthermore, same/increased partner numbers during lockdown (class 3, 18%; class 4, 56%) and postlockdown (class 3, 36%; class 4, 42%) compared with prelockdown was often reported. Of individuals who wanted an STI test during the pandemic, 62% in class 3 and 56% in class 4 did not get tested, mainly because they were unable to get an appointment. CONCLUSIONS: A subgroup of individuals, characterized by low health goals, negative infection prevention attitudes, and high impulsiveness, engaged in high-risk behavior during the pandemic. Identifying these individuals may help provide appropriate health care during strict lockdowns and after relaxation of measures.