In many countries where lockdown measures were relaxed early, such as the USA, parts of Australia, and some countries in western mainland Europe, resurgence of cases has been recorded.2 Informative ...data on epidemics derive from longitudinal (over time) cohort-based (following the same individuals) studies of seroprevalence of past infections and the incidence of new infections, stratified by age, gender, ethnicity, occupation, pre-existing health conditions, spatial home and work or school locations, and clinical outcomes. Uneven quality and slow access to information on COVID-19 spread and impact, collected by different government organisations, such as the Department of Health and Social Care, Public Health England, and NHS Trusts, have been major impediments to epidemiological analysis of the state of the epidemic and predictions of future trends (Anderson RM, Vegvari C, Baggaley RF, Hollingsworth TD, Maddren R, unpublished). The UK Government's advisory group, SAGE, has broadened the information they release to include the effective reproduction number, Rt, which describes the average number of secondary cases generated by primary cases at time t, and the epidemic growth rate, rt, which describes the rate of change in case numbers over a defined time.8,9 The value of rt is easier to estimate using simple statistical methods on changes in incidence over time. ...of importance is the probability distribution of the generation of secondary cases,17–19 which is overdispersed such that most infected individuals transmit none or a few infections, and a few individuals transmit many—the so-called super-spreading events.20 Contact tracing data provide crucial insights on this distribution, which has important consequences for COVID-19 control.21 A schematic representation of uncertainty in determining the magnitude of Rt and the course of the COVID-19 epidemic in the UK is shown in the figure with further information in the appendix.
Summary We did a systematic review and meta-analysis of observational studies of the risk of HIV-1 transmission per heterosexual contact. 43 publications comprising 25 different study populations ...were identified. Pooled female-to-male (0·04% per act 95% CI 0·01–0·14) and male-to-female (0·08% per act 95% CI 0·06–0·11) transmission estimates in high-income countries indicated a low risk of infection in the absence of antiretrovirals. Low-income country female-to-male (0·38% per act 95% CI 0·13–1·10) and male-to-female (0·30% per act 95% CI 0·14–0·63) estimates in the absence of commercial sex exposure (CSE) were higher. In meta-regression analysis, the infectivity across estimates in the absence of CSE was significantly associated with sex, setting, the interaction between setting and sex, and antenatal HIV prevalence. The pooled receptive anal intercourse estimate was much higher (1·7% per act 95% CI 0·3–8·9). Estimates for the early and late phases of HIV infection were 9·2 (95% CI 4·5–18·8) and 7·3 (95% CI 4·5–11·9) times larger, respectively, than for the asymptomatic phase. After adjusting for CSE, presence or history of genital ulcers in either couple member increased per-act infectivity 5·3 (95% CI 1·4–19·5) times versus no sexually transmitted infection. Study estimates among non-circumcised men were at least twice those among circumcised men. Low-income country estimates were more heterogeneous than high-income country estimates, which indicates poorer study quality, greater heterogeneity of risk factors, or under-reporting of high-risk behaviour. Efforts are needed to better understand these differences and to quantify infectivity in low-income countries.
Background The human immunodeficiency virus (HIV) infectiousness of anal intercourse (AI) has not been systematically reviewed, despite its role driving HIV epidemics among men who have sex with men ...(MSM) and its potential contribution to heterosexual spread. We assessed the per-act and per-partner HIV transmission risk from AI exposure for heterosexuals and MSM and its implications for HIV prevention. Methods Systematic review and meta-analysis of the literature on HIV-1 infectiousness through AI was conducted. PubMed was searched to September 2008. A binomial model explored the individual risk of HIV infection with and without highly active antiretroviral therapy (HAART). Results A total of 62 643 titles were searched; four publications reporting per-act and 12 reporting per-partner transmission estimates were included. Overall, random effects model summary estimates were 1.4% 95% confidence interval (CI) 0.2–2.5) and 40.4% (95% CI 6.0–74.9) for per-act and per-partner unprotected receptive AI (URAI), respectively. There was no significant difference between per-act risks of URAI for heterosexuals and MSM. Per-partner unprotected insertive AI (UIAI) and combined URAI–UIAI risk were 21.7% (95% CI 0.2–43.3) and 39.9% (95% CI 22.5–57.4), respectively, with no available per-act estimates. Per-partner combined URAI–UIAI summary estimates, which adjusted for additional exposures other than AI with a ‘main’ partner 7.9% (95% CI 1.2–14.5), were lower than crude (unadjusted) estimates 48.1% (95% CI 35.3–60.8). Our modelling demonstrated that it would require unreasonably low numbers of AI HIV exposures per partnership to reconcile the summary per-act and per-partner estimates, suggesting considerable variability in AI infectiousness between and within partnerships over time. AI may substantially increase HIV transmission risk even if the infected partner is receiving HAART; however, predictions are highly sensitive to infectiousness assumptions based on viral load. Conclusions Unprotected AI is a high-risk practice for HIV transmission, probably with substantial variation in infectiousness. The significant heterogeneity between infectiousness estimates means that pooled AI HIV transmission probabilities should be used with caution. Recent reported rises in AI among heterosexuals suggest a greater understanding of the role AI plays in heterosexual sex lives may be increasingly important for HIV prevention.
A novel influenza A (H1N1) virus has spread rapidly across the globe. Judging its pandemic potential is difficult with limited data, but nevertheless essential to inform appropriate health responses. ...By analyzing the outbreak in Mexico, early data on international spread, and viral genetic diversity, we make an early assessment of transmissibility and severity. Our estimates suggest that 23,000 (range 6000 to 32,000) individuals had been infected in Mexico by late April, giving an estimated case fatality ratio (CFR) of 0.4% (range: 0.3 to 1.8%) based on confirmed and suspected deaths reported to that time. In a community outbreak in the small community of La Gloria, Veracruz, no deaths were attributed to infection, giving an upper 95% bound on CFR of 0.6%. Thus, although substantial uncertainty remains, clinical severity appears less than that seen in the 1918 influenza pandemic but comparable with that seen in the 1957 pandemic. Clinical attack rates in children in La Gloria were twice that in adults (<15 years of age: 61%; greater-than-or-equal15 years: 29%). Three different epidemiological analyses gave basic reproduction number (R₀) estimates in the range of 1.4 to 1.6, whereas a genetic analysis gave a central estimate of 1.2. This range of values is consistent with 14 to 73 generations of human-to-human transmission having occurred in Mexico to late April. Transmissibility is therefore substantially higher than that of seasonal flu, and comparable with lower estimates of R₀ obtained from previous influenza pandemics.
As HIV is very effectively acquired during condomless receptive anal intercourse (AI) with serodiscordant and viremic partners, the practice could contribute to the high prevalence among female sex ...workers (FSW) in eSwatini (formerly known as Swaziland). We aim to estimate the proportion reporting AI (AI prevalence) among Swazi FSW and to identify the correlates of AI practice in order to better inform HIV prevention interventions among this population.
Using respondent-driven sampling (RDS), 325 Swazi FSW were recruited in 2011. We estimated the prevalence of AI and AI with inconsistent condom use in the past month with any partner type, and inconsistent condom use during AI and vaginal intercourse (VI) by partner type. Univariate and multivariable logistic regression models were used to identify behavioural and structural correlates associated with AI and AI with inconsistent condom use.
RDS-adjusted prevalence of AI and AI with inconsistent condom use was high, at 44%95% confidence interval (95%CI):35-53%) and 34%95%CI:26-42%, respectively and did not vary by partner type. HIV prevalence was high in this sample of FSW (70%), but knowledge that AI increases HIV acquisition risk low, with only 10% identifying AI as the riskiest sex act. Those who reported AI were more likely to be better educated (adjusted odds ratio(aOR) = 1.9295%CI:1.03-3.57), to have grown up in rural areas (aOR = 1.9095%CI:1.09-3.32), have fewer new clients in the past month (aOR = 0.3395%CI:0.16-0.68), and for last sex with clients to be condomless (aOR = 2.0995%CI:1.07-4.08). Although FSW reporting AI in past month were more likely to have been raped (aOR = 1.9595%CI:1.05-3.65) and harassed because of being a sex worker (aOR = 2.0995%CI:1.16-3.74), they were also less likely to have ever been blackmailed (aOR = 0.5095%CI:0.25-0.98) or been afraid to walk in public places (aOR = 0.4695%CI:0.25-0.87). Correlates of AI with inconsistent condom use were similar to those of AI.
AI is commonly practised and condom use is inconsistent among Swazi FSW. Sex act data are needed to determine how frequently AI is practiced. Interventions to address barriers to condom use are needed, as are biomedical interventions that reduce acquisition risk during AI.
Background Regular vaccination against SARS-CoV-2 may be needed to maintain immunity in 'at-risk' populations, which include healthcare workers (HCWs). However, little is known about the proportion ...of HCWs who might be hesitant about receiving a hypothetical regular SARS-CoV-2 vaccination or the factors associated with this hesitancy. Methods Cross-sectional analysis of questionnaire data collected as part of UK-REACH, a nationwide, longitudinal cohort study of HCWs. The outcome measure was binary, either a participant indicated they would definitely accept regular SARS-CoV-2 vaccination if recommended or they indicated some degree of hesitancy regarding acceptance (probably accept or less likely). We used logistic regression to identify factors associated with hesitancy for receiving regular vaccination. Results A total of 5454 HCWs were included in the analysed cohort, 23.5% of whom were hesitant about regular SARS-CoV-2 vaccination. Black HCWs were more likely to be hesitant than White HCWs (aOR 2.60, 95%CI 1.80-3.72) as were those who reported a previous episode of COVID-19 (1.33, 1.13-1.57 vs those who tested negative). Those who received influenza vaccination in the previous two seasons were over five times less likely to report hesitancy for regular SARS-CoV-2 vaccination than those not vaccinated against influenza in either season (0.18, 0.14-0.21). HCWs who trusted official sources of vaccine information (such as NHS or government adverts or websites) were less likely to report hesitancy for a regular vaccination programme. Those who had been exposed to information advocating against vaccination from friends and family were more likely to be hesitant. Conclusions In this study, nearly a quarter of UK HCWs were hesitant about receiving a regular SARS-CoV-2 vaccination. We have identified key factors associated with hesitancy for regular SARS-CoV-2 vaccination, which can be used to identify groups of HCWs at the highest risk of vaccine hesitancy and tailor interventions accordingly. Family and friends of HCWs may influence decisions about regular vaccination. This implies that working with HCWs and their social networks to allay concerns about SARS-CoV-2 vaccination could improve uptake in a regular vaccination programme. Trial registration ISRCTN Registry, ISRCTN11811602. Keywords: Healthcare, Ethnicity, SARS-CoV-2, COVID-19, Vaccination, Hesitancy
Screening and treatment for latent tuberculosis infection (LTBI) are key for TB control. In the UK, the National Institute for Health and Care Excellence (NICE) and the British HIV Association ...(BHIVA) give conflicting guidance on which groups of people with HIV (PWH) should be screened, and previous national analysis demonstrated heterogeneity in how guidance is applied. There is an urgent need for a firmer clinical effectiveness evidence base on which to build screening policy.
We conducted a systematic, programmatic LTBI-screening intervention for all PWH receiving care in Leicester, UK. We compared yields (percentage IGRA positive) and number of tests required when applying the NICE and BHIVA testing strategies, as well as strategies targeting screening by TB incidence in patients' countries of birth.
Of 1053 PWH tested, 118 were IGRA-positive (11.2%). Positivity was associated with higher TB incidence in country-of-birth adjusted odds ratio, 50-149 cases compared with <50 cases/100 000: 11.6; 95% confidence interval (CI) 4.79-28.10). There was high testing uptake (1053/1069, 98.5%). Appropriate chemoprophylaxis was commenced in 100 of 117 (85.5%) patients diagnosed with LTBI, of whom 96 of 100 (96.0%) completed treatment. Delivering targeted testing to PWH from countries with TB incidence greater than 150 per 100 000 population or any sub-Saharan African country, would have correctly identified 89.8% of all LTBI cases while cutting tests required by 46.1% compared with NICE guidance, performing as well as BHIVA 2018 guidance.
Targeting screening to higher risk PWH increases yield and reduces the number requiring testing. Our proposed 'PWH-LTBI streamlined guidance' offers a simplified approach, with the potential to improve national LTBI-screening implementation.
In The Lancet today, Reuben Granich and colleagues use mathematical models to show that annual screening of most adults for HIV, with immediate commencement of antiretroviral therapy (ART) for all ...those infected, would dramatically reduce HIV incidence.1 This strategy would be a bold move away from the current approach of treatment on the basis of clinical need, in which the hoped-for synergies between treatment and prevention will remain limited because testing and counselling focus on individuals who have probably already transmitted infection.2 The "treat early, treat hard" approach of the early era of triple ART fell out of favour due to drug toxicities, concerns over the evolution of drug resistance, and potential limits to the duration of treatment efficacy in the patient. Therefore, when Velasco-Hernandez and colleagues first showed in simple models that ART could eliminate HIV infection, their findings appeared extremely unrealistic.5 Since then, clinical opinions have changed with improved regimens and evidence of lower death rates if ART is started before CD4+ cell counts fall below 350 per µL, which makes earlier treatment more acceptable.4 When early treatment is considered as a prevention tool, success will require substantial resources and depend on a remarkable degree of acceptance and cooperation across populations.
Abstract
The World Health Organization’s (WHO’s) 2030 road map for neglected tropical diseases (NTDs) emphasizes the importance of strengthened, institutionalized “post-elimination” surveillance. The ...required shift from disease-siloed, campaign-based programming to routine, integrated surveillance and response activities presents epidemiological, logistical, and financial challenges, yet practical guidance on implementation is lacking. Nationally representative survey programs, such as demographic and health surveys (DHS), may offer a platform for the integration of NTD surveillance within national health systems and health information systems. Here, we describe characteristics of DHS and other surveys conducted within the WHO Africa region in terms of frequency, target populations, and sample types and discuss applicability for post-validation and post-elimination surveillance. Maximizing utility depends not only on the availability of improved diagnostics but also on better understanding of the spatial and temporal dynamics of transmission at low prevalence. To this end, we outline priorities for obtaining additional data to better characterize optimal post-elimination surveillance platforms.
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