All Publications

  • Systematic identification and replication of factors associated with human papillomavirus vaccine initiation among adolescents in the United States using an environment-wide association study approach. Sexually transmitted infections Nasserie, T., Bendavid, E. 2021


    OBJECTIVE: Human papillomavirus (HPV) vaccination coverage is low among adolescents in the USA. Identification of factors associated with HPV vaccine initiation (receipt of ≥1dose) is critical for improving uptake. Our objective was to systematically investigate all eligible factors available in a nationally representative sample of adolescents to identify drivers of HPV vaccine initiation using a novel methodological approach.METHODS: We performed multiple cross-sectional analyses using data from the adolescent component of the National Immunization Surveys (NIS)-Teen between 2014 and 2019. Study participants were parents or caregivers of adolescents aged 13-17 years. Exposure variables measured sociodemographic and geographical characteristics, health conditions and healthcare provision. We tested the association between each factor and HPV vaccine initiation using univariate logistic regression and multivariate logistic regression adjusted for mother's age, mother's education level, mother's marital status, poverty status and adolescent's sex. We validated findings for each type of analysis within surveys, between surveys (across years 2014-2019) and across several subgroups (age, sex, poverty status and race/ethnicity).RESULTS: Six factors were replicated in the multivariate analysis. Most replicated factors characterised the role of healthcare providers and healthcare-seeking behaviours. After adjustment, provider HPV recommendation remained the most strongly associated with HPV vaccine initiation (2019 NIS-Teen: OR 13.4, 95% CI 11.3 to 17.3, p<0.001). The variance explained by a full model including replicated factors was 0.39.CONCLUSIONS: This is the first study to explore the association between all available factors in the NIS-Teen and HPV vaccine initiation in a systematic manner. Our study suggests that healthcare-seeking behaviours and interactions with the health system may be drivers of HPV vaccine initiation and warrant further study. Addressing these factors could improve the rate of HPV vaccine initiation among adolescents in the USA.

    View details for DOI 10.1136/sextrans-2021-054976

    View details for PubMedID 34039744

  • Assessment of the Frequency and Variety of Persistent Symptoms Among Patients With COVID-19: A Systematic Review. JAMA network open Nasserie, T., Hittle, M., Goodman, S. N. 2021; 4 (5): e2111417


    Importance: Infection with COVID-19 has been associated with long-term symptoms, but the frequency, variety, and severity of these complications are not well understood. Many published commentaries have proposed plans for pandemic control that are primarily based on mortality rates among older individuals without considering long-term morbidity among individuals of all ages. Reliable estimates of such morbidity are important for patient care, prognosis, and development of public health policy.Objective: To conduct a systematic review of studies examining the frequency and variety of persistent symptoms after COVID-19 infection.Evidence Review: A search of PubMed and Web of Science was conducted to identify studies published from January 1, 2020, to March 11, 2021, that examined persistent symptoms after COVID-19 infection. Persistent symptoms were defined as those persisting for at least 60 days after diagnosis, symptom onset, or hospitalization or at least 30 days after recovery from the acute illness or hospital discharge. Search terms included COVID-19, SARS-CoV-2, coronavirus, 2019-nCoV, long-term, after recovery, long-haul, persistent, outcome, symptom, follow-up, and longitudinal. All English-language articles that presented primary data from cohort studies that reported the prevalence of persistent symptoms among individuals with SARS-CoV-2 infection and that had clearly defined and sufficient follow-up were included. Case reports, case series, and studies that described symptoms only at the time of infection and/or hospitalization were excluded. A structured framework was applied to appraise study quality.Findings: A total of 1974 records were identified; of those, 1247 article titles and abstracts were screened. After removal of duplicates and exclusions, 92 full-text articles were assessed for eligibility; 47 studies were deemed eligible, and 45 studies reporting 84 clinical signs or symptoms were included in the systematic review. Of 9751 total participants, 5266 (54.0%) were male; 30 of 45 studies reported mean or median ages younger than 60 years. Among 16 studies, most of which comprised participants who were previously hospitalized, the median proportion of individuals experiencing at least 1 persistent symptom was 72.5% (interquartile range [IQR], 55.0%-80.0%). Individual symptoms occurring most frequently included shortness of breath or dyspnea (26 studies; median frequency, 36.0%; IQR, 27.6%-50.0%), fatigue or exhaustion (25 studies; median frequency, 40.0%; IQR, 31.0%-57.0%), and sleep disorders or insomnia (8 studies; median 29.4%, IQR, 24.4%-33.0%). There were wide variations in the design and quality of the studies, which had implications for interpretation and often limited direct comparability and combinability. Major design differences included patient populations, definitions of time zero (ie, the beginning of the follow-up interval), follow-up lengths, and outcome definitions, including definitions of illness severity.Conclusions and Relevance: This systematic review found that COVID-19 symptoms commonly persisted beyond the acute phase of infection, with implications for health-associated functioning and quality of life. Current studies of symptom persistence are highly heterogeneous, and future studies need longer follow-up, improved quality, and more standardized designs to reliably quantify risks.

    View details for DOI 10.1001/jamanetworkopen.2021.11417

    View details for PubMedID 34037731

  • Association between air travel and importation of chikungunya into the United States. Journal of travel medicine Nasserie, T. n., Brent, S. E., Tuite, A. R., Moineddin, R. n., Yong, J. H., Miniota, J. n., Bogoch, I. I., Watts, A. G., Khan, K. n. 2019


    During infectious disease outbreaks with pandemic potential, the number of air passengers travelling from the outbreak source to international destinations has been used as a proxy for disease importation risk to new locations. However, evaluations of the validity of this approach are limited. We sought to quantify the association between international air travel and disease importation using the 2014-2016 chikungunya outbreak in the Americas as a case study.We used country-level chikungunya case data to define a time period of epidemic activity for each the 45 countries and territories in the Americas reporting outbreaks between 2014 and 2016. For each country, we identified airports within or proximate to areas considered suitable for chikungunya transmission and summed the number of commercial air passengers departing from these airports during the epidemic period to each United States (U.S.) state. We used negative binomial models to quantify the association between the number of incoming air passengers from countries experiencing chikungunya epidemics and the annual rate of chikungunya importation into the United States at the state level.We found a statistically significant positive association between passenger flows via airline travel from countries experiencing chikungunya epidemics and the number of imported cases in the United States at the state level (p<0.0001). Additionally, we found that as the number of arriving airline passengers increased by 10%, the estimated number of imported cases increased by 5.2% (95% CI: 3.0-7.6).This validation study demonstrated that air travel was strongly associated with observed importation of chikungunya cases in the United States and can be a useful proxy for identifying areas at increased risk for disease importation. This approach may be useful for understanding exportation risk of other arboviruses.

    View details for PubMedID 31011752