Last data update: Sep 23, 2024. (Total: 47723 publications since 2009)
Records 1-7 (of 7 Records) |
Query Trace: Clay PA [original query] |
---|
Modelling the impact of vaccination and sexual behaviour adaptations on mpox cases in the USA during the 2022 outbreak
Clay PA , Asher JM , Carnes N , Copen CE , Delaney KP , Payne DC , Pollock ED , Mermin J , Nakazawa Y , Still W , Mangla AT , Spicknall IH . Sex Transm Infect 2023 BACKGROUND: The 2022 mpox outbreak has infected over 30 000 people in the USA, with cases declining since mid-August. Infections were commonly associated with sexual contact between men. Interventions to mitigate the outbreak included vaccination and a reduction in sexual partnerships. Understanding the contributions of these interventions to decreasing cases can inform future public health efforts. METHODS: We fit a dynamic network transmission model to mpox cases reported by Washington DC through 10 January 2023. This model incorporated both vaccine administration data and reported reductions in sexual partner acquisition by gay, bisexual or other men who have sex with men (MSM). The model output consisted of daily cases over time with or without vaccination and/or behavioural adaptation. RESULTS: We found that initial declines in cases were likely caused by behavioural adaptations. One year into the outbreak, vaccination and behavioural adaptation together prevented an estimated 84% (IQR 67% to 91%) of cases. Vaccination alone averted 79% (IQR 64% to 88%) of cases and behavioural adaptation alone averted 25% (IQR 10% to 42%) of cases. We further found that in the absence of vaccination, behavioural adaptation would have reduced the number of cases, but would have prolonged the outbreak. CONCLUSIONS: We found that initial declines in cases were likely caused by behavioural adaptation, but vaccination averted more cases overall and was key to hastening outbreak conclusion. Overall, this indicates that outreach to encourage individuals to protect themselves from infection was vital in the early stages of the mpox outbreak, but that combination with a robust vaccination programme hastened outbreak conclusion. |
Using infection prevalence, seroprevalence and case report data to estimate chlamydial infection incidence
Clay PA , Pollock ED , Copen CE , Anyalechi GE , Danavall DC , Hong J , Khosropour CM , Galloway E , Spicknall IH . Sex Transm Infect 2023 99 (8) 513-519 OBJECTIVES: To measure the effectiveness of chlamydia control strategies, we must estimate infection incidence over time. Available data, including survey-based infection prevalence and case reports, have limitations as proxies for infection incidence. We therefore developed a novel method for estimating chlamydial incidence. METHODS: We linked a susceptible infectious mathematical model to serodynamics data from the National Health and Nutritional Examination Survey, as well as to annual case reports. We created four iterations of this model, varying assumptions about how the method of infection clearance (via treatment seeking, routine screening or natural clearance) relates to long-term seropositivity. Using these models, we estimated annual infection incidence for women aged 18-24 and 25-37 years in 2014. To assess model plausibility, we also estimated natural clearance for the same groups. RESULTS: Of the four models we analysed, the model that best explained the empirical data was the one in which longer-lasting infections, natural clearance and symptomatic infections all increased the probability of long-term seroconversion. Using this model, we estimated 5910 (quartile (Q)1, 5330; Q3, 6500) incident infections per 100 000 women aged 18-24 years and 2790 (Q1, 2500; Q3, 3090) incident infections per 100 000 women aged 25-37 years in 2014. Furthermore, we estimated that natural clearance rates increased with age. CONCLUSIONS: Our method can be used to estimate the number of chlamydia infections each year, and thus whether infection incidence increases or decreases over time and after policy changes. Furthermore, our results suggest that clearance via medical intervention may lead to short-term or no seroconversion, and the duration of untreated chlamydial infection may vary with age, underlining the complexity of chlamydial infection dynamics. |
Modelling the impact of vaccination and sexual behavior change on reported cases of mpox in Washington D.C (preprint)
Clay PA , Asher JM , Carnes N , Copen CE , Delaney KP , Payne DC , Pollock ED , Mermin J , Nakazawa Y , Still W , Mangla AT , Spicknall IH . medRxiv 2023 14 Background: The 2022 mpox outbreak infected over 30,000 people in the United States. Infections were commonly associated with sexual contact between men. Interventions included vaccination and reductions in sexual partnerships. We estimated the averted infections attributable to each intervention using mathematical modeling. Method(s): We fit a dynamic network transmission model to mpox cases reported by the District of Columbia through January 2023. We incorporated vaccine administration data and reported reductions in sexual partnerships among gay, bisexual, or other men who have sex with men (MSM). Model output consisted of predicted cases over time with or without vaccination and/or behavior change. Result(s): We estimated initial case reductions were due to behavior change. Vaccination alone averted 64% [IQR:57%-72%] and behavior change alone averted 21% [IQR:11%-29%] of cases. Vaccination and behavior change together averted 80% [IQR:74%-85%] of cases. In the absence of vaccination, behavior change reduced cumulative cases but also prolonged the outbreak. Conclusion(s): Initial case declines were likely caused by behavior change, but vaccination averted more cases overall. Overall, this indicates that encouraging individuals to protect themselves was vital in the early outbreak, but that combination with a robust vaccination program was ultimately required for control. Copyright The copyright holder for this preprint is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. This article is a US Government work. It is not subject to copyright under 17 USC 105 and is also made available for use under a CC0 license. |
Potential for recurrent mpox outbreaks among gay, bisexual, and other men who have sex with men - United States, 2023
Pollock ED , Clay PA , Keen A , Currie DW , Carter RJ , Quilter LAS , Gundlapalli AV , Mermin J , Spicknall IH . MMWR Morb Mortal Wkly Rep 2023 72 (21) 568-573 More than 30,000 monkeypox (mpox) cases have been diagnosed in the United States since May 2022, primarily among gay, bisexual, and other men who have sex with men (MSM) (1,2). In recent months, diagnoses have declined to one case per day on average. However, mpox vaccination coverage varies regionally, suggesting variable potential risk for mpox outbreak recurrence (3). CDC simulated dynamic network models representing sexual behavior among MSM to estimate the risk for and potential size of recurrent mpox outbreaks at the jurisdiction level for 2023 and to evaluate the benefits of vaccination for preparedness against mpox reintroduction. The risk for outbreak recurrence after mpox reintroduction is linearly (inversely) related to the proportion of MSM who have some form of protective immunity: the higher the population prevalence of immunity (from vaccination or natural infection), the lower the likelihood of recurrence in that jurisdiction across all immunity levels modeled. In contrast, the size of a potential recurrent outbreak might have thresholds: very small recurrences are predicted for jurisdictions with mpox immunity of 50%-100%; exponentially increasing sizes of recurrences are predicted for jurisdictions with 25%-50% immunity; and linearly increasing sizes of recurrences are predicted for jurisdictions with <25% immunity. Among the 50 jurisdictions examined, 15 are predicted to be at minimal risk for recurrence because of their high levels of population immunity. This analysis underscores the ongoing need for accessible and sustained mpox vaccination to decrease the risk for and potential size of future mpox recurrences. |
Updated estimate of the annual direct medical cost of screening and treatment for human papillomavirus associated disease in the United States
Clay PA , Thompson TD , Markowitz LE , Ekwueme DU , Saraiya M , Chesson HW . Vaccine 2023 41 (14) 2376-2381 The annual direct medical cost attributable to human papillomavirus (HPV) in the United States over the period 2004-2007 was estimated at $9.36 billion in 2012 (updated to 2020 dollars). The purpose of this report was to update that estimate to account for the impact of HPV vaccination on HPV-attributable disease, reductions in the frequency of cervical cancer screening, and new data on the cost per case of treating HPV-attributable cancers. Based primarily on data from the literature, we estimated the annual direct medical cost burden as the sum of the costs of cervical cancer screening and follow-up and the cost of treating HPV-attributable cancers, anogenital warts, and recurrent respiratory papillomatosis (RRP). We estimated the total direct medical cost of HPV to be $9.01 billion annually over the period 2014-2018 (2020 U.S. dollars). Of this total cost, 55.0% was for routine cervical cancer screening and follow-up, 43.8% was for treatment of HPV-attributable cancer, and less than 2% was for treating anogenital warts and RRP. Although our updated estimate of the direct medical cost of HPV is slightly lower than the previous estimate, it would have been substantially lower had we not incorporated more recent, higher cancer treatment costs. |
Estimated Incidence and Prevalence of Gonorrhea in the United States, 2006-2019.
Pollock ED , Clay PA , Kreisel KM , Spicknall IH . Sex Transm Dis 2023 50 (4) 188-195 BACKGROUND: We extend recent work estimating incidence and prevalence of gonococcal infections among men and women aged 15-39 years in the US in 2018 by applying the same modeling framework to estimate gonococcal incidence and prevalence during 2006-2019. METHODS: The model is informed by cases from the Nationally Notifiable Disease Surveillance System, data from the National Survey of Family Growth, and data on other factors known to impact gonococcal incidence and prevalence. We use Monte Carlo simulation to account for uncertainty in input parameters. Results are reported as median annual per-capita incidence and prevalence; uncertainty intervals are characterized by the 25th and 75th simulated percentiles. RESULTS: 1,603,473 (1,467,801-1,767,779) incident cases of gonorrhea were estimated in 2019. Per-capita incidence increased 32%, from 1101 (1002-1221) to 1456 (1333-1605) infections per 100,000 persons. This trend in per-capita incidence had three phrases: an initial decline during 2006-2009, a plateau through 2013, and a rapid increase of 66% through 2019. Men aged 25-39 experienced the greatest increase in incidence (125%, 541 (467-651) to 1212 infections (1046-1458) per 100,000 men). Women aged 25-39 had the lowest incidence in 2019, with 1040 infections (882-1241) per 100,000 women. Prevalence increased more slowly among those aged 25-39 vs. 15-24. The incidence ratio comparing men to women aged 25-39 increased from 0.76 to 1.18. CONCLUSIONS: The burden of gonorrhea has increased among men and women aged 15-39 years since 2013. An increasing proportion of incident infections are among men. Additional biomedical and behavioral interventions are needed to control gonococcal transmission. |
Modeling the impact of sexual networks in the transmission of monkeypox virus among gay, bisexual, and other men who have sex with men - United States, 2022
Spicknall IH , Pollock ED , Clay PA , Oster AM , Charniga K , Masters N , Nakazawa YJ , Rainisch G , Gundlapalli AV , Gift TL . MMWR Morb Mortal Wkly Rep 2022 71 (35) 1131-1135 What is already known about this topic? The 2022 monkeypox outbreak is associated with sexual and intimate contact. Survey data suggest that gay, bisexual, and other men who have sex with men (MSM), who have been disproportionately affected, are reducing one-time partnerships. What is added by this report? Modeling of sexual infection transmission between men indicates that one-time partnerships, which account for 3% of daily sexual partnerships and 16% of daily sex acts, account for approximately 50% of daily Monkeypox virus (MPXV) transmission. A 40% reduction in one-time partnerships might delay the spread of monkeypox and reduce the percentage of persons infected by 20% to 31%. What are the implications for public health practice? Reductions in one-time partnerships, already being reported by MSM, might significantly reduce MPXV transmission. © 2022 Department of Health and Human Services. All rights reserved. |
- Page last reviewed:Feb 1, 2024
- Page last updated:Sep 23, 2024
- Content source:
- Powered by CDC PHGKB Infrastructure