Relative Risk of COVID-19 Reinfection by Demographic and Vaccination Factors During the Period March 2020-October 2022.

The risk of reinfection has been difficult to quantify throughout the pandemic, making the case for COVID-19 vaccination and receipt of booster doses to the public difficult for the public health community. To address this question, Michigan statewide COVID-19 infection and vaccination data was utilized in this cross-sectional study to determine the risk of reinfection by vaccination status. Cases were divided into subgroups by vaccination status, and the risk of reinfection in the various vaccination categories was then calculated by dividing the cumulative incidence of reinfection in a vaccine category by the cumulative incidence of reinfection of those not in that category Within this population, the risk of becoming reinfected was 1.6 times higher for those who were unvaccinated than those who were vaccinated; those with a primary series saw a 27% reduced risk of reinfections compared to those without a primary series. Those with an additional booster dose had a modest improvement, with 35% reduced risk of reinfection when compared to the other groups combined. These results provide population level data to support current public health vaccination recommendations.

Evaluation of Public Health Contact Tracing for Mpox Among Gay, Bisexual, and Other Men Who Have Sex With Men-10 US Jurisdictions, May 17-July 31, 2022.

Objectives. To examine the potential impact of contact tracing to identify contacts and prevent mpox transmission among gay, bisexual, and other men who have sex with men (MSM) as the outbreak expanded. Methods. We assessed contact tracing outcomes from 10 US jurisdictions before and after access to the mpox vaccine was expanded from postexposure prophylaxis for persons with known exposure to include persons at high risk for acquisition (May 17-June 30, 2022, and July 1-31, 2022, respectively). Results. Overall, 1986 mpox cases were reported in MSM from included jurisdictions (240 before expanded vaccine access; 1746 after expanded vaccine access). Most MSM with mpox were interviewed (95.0% before vaccine expansion and 97.0% after vaccine expansion); the proportion who named at least 1 contact decreased during the 2 time periods (74.6% to 38.9%). Conclusions. During the period when mpox cases among MSM increased and vaccine access expanded, contact tracing became less efficient at identifying exposed contacts. Public Health Implications. Contact tracing was more effective at identifying persons exposed to mpox in MSM sexual and social networks when case numbers were low, and it could be used to facilitate vaccine access. (Am J Public Health. 2023;113(7):815-818. https://doi.org/10.2105/AJPH.2023.307301).

COVID-19 Incidence and Mortality Among Unvaccinated and Vaccinated Persons Aged ≥12 Years by Receipt of Bivalent Booster Doses and Time Since Vaccination - 24 U.S. Jurisdictions, October 3, 2021-December 24, 2022.

On September 1, 2022, CDC recommended an updated (bivalent) COVID-19 vaccine booster to help restore waning protection conferred by previous vaccination and broaden protection against emerging variants for persons aged ≥12 years (subsequently extended to persons aged ≥6 months).* To assess the impact of original (monovalent) COVID-19 vaccines and bivalent boosters, case and mortality rate ratios (RRs) were estimated comparing unvaccinated and vaccinated persons aged ≥12 years by overall receipt of and by time since booster vaccination (monovalent or bivalent) during Delta variant and Omicron sublineage (BA.1, BA.2, early BA.4/BA.5, and late BA.4/BA.5) predominance.† During the late BA.4/BA.5 period, unvaccinated persons had higher COVID-19 mortality and infection rates than persons receiving bivalent doses (mortality RR = 14.1 and infection RR = 2.8) and to a lesser extent persons vaccinated with only monovalent doses (mortality RR = 5.4 and infection RR = 2.5). Among older adults, mortality rates among unvaccinated persons were significantly higher than among those who had received a bivalent booster (65-79 years; RR = 23.7 and ≥80 years; 10.3) or a monovalent booster (65-79 years; 8.3 and ≥80 years; 4.2). In a second analysis stratified by time since booster vaccination, there was a progressive decline from the Delta period (RR = 50.7) to the early BA.4/BA.5 period (7.4) in relative COVID-19 mortality rates among unvaccinated persons compared with persons receiving who had received a monovalent booster within 2 weeks-2 months. During the early BA.4/BA.5 period, declines in relative mortality rates were observed at 6-8 (RR = 4.6), 9-11 (4.5), and ≥12 (2.5) months after receiving a monovalent booster. In contrast, bivalent boosters received during the preceding 2 weeks-2 months improved protection against death (RR = 15.2) during the late BA.4/BA.5 period. In both analyses, when compared with unvaccinated persons, persons who had received bivalent boosters were provided additional protection against death over monovalent doses or monovalent boosters. Restored protection was highest in older adults. All persons should stay up to date with COVID-19 vaccination, including receipt of a bivalent booster by eligible persons, to reduce the risk for severe COVID-19.

Trends in Laboratory-Confirmed SARS-CoV-2 Reinfections and Associated Hospitalizations and Deaths Among Adults Aged ≥18 Years - 18 U.S. Jurisdictions, September 2021-December 2022.

Although reinfections with SARS-CoV-2 have occurred in the United States with increasing frequency, U.S. epidemiologic trends in reinfections and associated severe outcomes have not been characterized. Weekly counts of SARS-CoV-2 reinfections, total infections, and associated hospitalizations and deaths reported by 18 U.S. jurisdictions during September 5, 2021-December 31, 2022, were analyzed overall, by age group, and by five periods of SARS-CoV-2 variant predominance (Delta and Omicron [BA.1, BA.2, BA.4/BA.5, and BQ.1/BQ.1.1]). Among reported reinfections, weekly trends in the median intervals between infections and frequencies of predominant variants during previous infections were calculated. As a percentage of all infections, reinfections increased substantially from the Delta (2.7%) to the Omicron BQ.1/BQ.1.1 (28.8%) periods; during the same periods, increases in the percentages of reinfections among COVID-19-associated hospitalizations (from 1.9% [Delta] to 17.0% [Omicron BQ.1/BQ.1.1]) and deaths (from 1.2% [Delta] to 12.3% [Omicron BQ.1/BQ.1.1]) were also substantial. Percentages of all COVID-19 cases, hospitalizations, and deaths that were reinfections were consistently higher across variant periods among adults aged 18-49 years compared with those among adults aged ≥50 years. The median interval between infections ranged from 269 to 411 days by week, with a steep decline at the start of the BA.4/BA.5 period, when >50% of reinfections occurred among persons previously infected during the Alpha variant period or later. To prevent severe COVID-19 outcomes, including those following reinfection, CDC recommends staying up to date with COVID-19 vaccination and receiving timely antiviral treatments, when eligible.

Invasive Group A Streptococcus Outbreaks Associated with Home Healthcare, England, 2018-2019.

Healthcare-associated invasive group A Streptococcus (iGAS) outbreaks are common worldwide, but only England has reported outbreaks associated with home healthcare (HHC). We describe 10 outbreaks during 2018-2019 in England. A total of 96 iGAS cases (range 2-39 per outbreak) and 28 deaths (case-fatality rate 29%) occurred. Outbreak duration ranged from 3-517 days; median time between sequential cases was 20.5 days (range 1-225 days). Outbreak identification was difficult, but emm typing and whole-genome sequencing improved detection. Network analyses indicated multiple potential transmission routes. Screening of 366 HHC workers from 9 outbreaks identified group A Streptococcus carriage in just 1 worker. Outbreak control required multiple interventions, including improved infection control, equipment decontamination, and antimicrobial prophylaxis for staff. Transmission routes and effective interventions are not yet clear, and iGAS outbreaks likely are underrecognized. To improve patient safety and reduce deaths, public health agencies should be aware of HHC-associated iGAS.

Trends in surgical site infections following orthopaedic surgery.

PURPOSE OF REVIEW: This review presents an update on recent findings relating to the prevention, control and epidemiology of infections following orthopaedic surgery. RECENT FINDINGS: Trends in population rates and characteristics of patients undergoing hip and knee replacement surgery, coupled with the reported excess infection risk in obese patients, emphasize the current and future impact of increasing population obesity on healthcare delivery. SUMMARY: Prevention of orthopaedic infection is dependent on elimination or optimal management of documented risk factors. Guidelines and quality standards play a key role in translating this evidence base into a framework of practices for the prevention of surgical site infections. Increasing levels of orthopaedic infection due to Enterobacteriaceae, coupled with an increasingly obese surgical population may necessitate a reassessment of antimicrobial prophylaxis strategies.

Factors Associated with HIV Seroconversion Among Women Attending an Urban Health Clinic in the South: A Matched Case-Control Study.

Compared to knowledge about HIV risk factors among men in the south, less is known about risk factors for women. We conducted an individually matched case-control study to identify factors associated with HIV seroconversion among women. Cases had a clinician-assisted visit (CAV) between 2011 and 2016 at an Atlanta-based public health clinic before HIV diagnosis. Controls were women who visited the clinic but remained HIV negative. Controls were matched to cases in a 2:1 ratio on race, age at first CAV, and date of first CAV. Conditional logistic regression was used to develop a best-fitting model for characterizing HIV risk. Of 18,281 women who were HIV negative at their first visit, 110 (0.6%) seroconverted before 2019. Of these, 80 (73%) had a CAV before HIV diagnosis. Having multiple gonorrhea episodes, a syphilis episode, a greater number of sex partners in the past 2 months, anal sex, history of drug use, history of exchanging drugs or money for sex, and heterosexual sex with >1 sex partner in the last month were individually associated with HIV seroconversion. In multivariate analyses, having a syphilis episode [odds ratio (OR) = 4.7, 95% confidence interval (CI): 1.3-16.3], anal sex (OR = 2.8, 95% CI: 1.0-8.1), and injection drug or crack cocaine use (OR = 33.5, 95% CI: 3.6-313.3) remained associated with HIV. Women having all three risk factors were six times more likely to seroconvert compared to women without these factors. Our results offer insights into which women in a southern HIV "hotspot" may be at greatest risk for HIV.

Cost-benefit analysis of surveillance for surgical site infection following caesarean section.

OBJECTIVE: To estimate the economic burden to the health service of surgical site infection following caesarean section and to identify potential savings achievable through implementation of a surveillance programme. DESIGN: Economic model to evaluate the costs and benefits of surveillance from community and hospital healthcare providers' perspective. SETTING: England. PARTICIPANTS: Women undergoing caesarean section in National Health Service hospitals. MAIN OUTCOME MEASURE: Costs attributable to treatment and management of surgical site infection following caesarean section. RESULTS: The costs (2010) for a hospital carrying out 800 caesarean sections a year based on infection risk of 9.6% were estimated at £18 914 (95% CI 11 521 to 29 499) with 28% accounted for by community care (£5370). With inflation to 2019 prices, this equates to an estimated cost of £5.0 m for all caesarean sections performed annually in England 2018-2019, approximately £1866 and £93 per infection managed in hospital and community, respectively. The cost of surveillance for a hospital for one calendar quarter was estimated as £3747 (2010 costs). Modelling a decrease in risk of infection of 30%, 20% or 10% between successive surveillance periods indicated that a variable intermittent surveillance strategy achieved higher or similar net savings than continuous surveillance. Breakeven was reached sooner with the variable surveillance strategy than continuous surveillance when the baseline risk of infection was 10% or 15% and smaller loses with a baseline risk of 5%. CONCLUSION: Surveillance of surgical site infections after caesarean section with feedback of data to surgical teams offers a potentially effective means to reduce infection risk, improve patient experience and save money for the health service.

Is It Valid to Compare Surgical Site Infections Rates Between Countries? Insights From a Study of English and Norwegian Surveillance Systems.

OBJECTIVE To assess whether differences in surveillance methods or underlying populations significantly influence internationally reported national SSI rates by comparing surveillance data from 2 countries. DESIGN Retrospective cohort. SETTING England and Norway. METHODS We assessed the population under surveillance and surveillance methodology to compare SSI rates in 2 countries (September 2012-January 2015) for 4 surgical categories: coronary artery bypass graft (CABG), colon surgery, cholecystectomy, and hip prosthesis (HPRO). We compared the inpatient SSI incidence using logistic regression, adjusting for the following known risk factors: sex, age, ASA score, wound class, postoperative hospital days, and operation duration. Subsequently, we restricted further analyses to the procedures reported by both countries. RESULTS There were important differences in case definitions for superficial infection, so we restricted our analyses to deep incisional and organ-space SSIs. For CABG, the crude odds ratio (OR) for England compared to Norway was 2.4 (95% CI, 1.4-4.4), whereas adjusted OR (aOR) lost significance (aOR, 1.1; 95% CI, 0.57-2.0). For colon surgery the decreased odds (OR, 0.68; 95% CI, 0.56-0.81) remained significant after adjustment (aOR, 0.42; 95% CI, 0.34-0.51). We found no associations for cholecystectomy. For HPRO, the crude OR suggested no significant difference (OR, 1.2; 95% CI, 0.72-2.1), whereas the aOR was significantly lower in England (aOR, 0.45; 95% CI, 0.25-0.81). Including only the subset of procedures reported by both countries yielded comparable results. CONCLUSION Differences in case definitions and population under surveillance in the English and Norwegian SSI surveillance systems affected SSI estimates, making the comparison of crude rates unreliable. Standardized definitions and adjustment for established risk factors are essential for European comparisons to guide related public health actions. Infect Control Hosp Epidemiol 2017;38:162-171.

Prevention of surgical site infection.

Surgical site infection (SSI) is a common healthcare-associated infection that can cause patients extreme pain and discomfort, resulting in prolonged hospitalisation and additional costs to the NHS. Multidisciplinary team working, combined with audit and surveillance, early recognition of signs and symptoms of infection, and implementation of evidence-based guidance are essential for reducing the incidence of SSI. Nurses caring for patients in the pre, peri and post-operative period have an important role in advising individuals about the risks associated with SSI and how infection should be managed.

Serious carbamazepine-induced hypersensitivity reactions associated with the HSP70 gene cluster.

OBJECTIVES: The use of carbamazepine (CBZ), the most commonly prescribed antiepileptic drug, is hampered by the occurrence of severe, potentially lethal hypersensitivity reactions. The pathogenesis of hypersensitivity is not yet known, but immune mechanisms are involved. Predisposition to CBZ hypersensitivity is likely to be genetically determined, and genes within the major histocompatibility complex (MHC) have been implicated. The heat shock protein (HSP70) gene cluster is located in the MHC class III region. METHODS: Using a case-control study design, we compared 61 patients with CBZ hypersensitivity (22 with a severe reaction) to 44 patients on CBZ with no signs of hypersensitivity and 172 healthy controls. The genotyping strategy involved identification of common and rare single nucleotide polymorphisms (SNPs) within the HSP70 gene cluster by sequencing, estimation of linkage disequilibrium (LD) and haplotype structure, and thereafter, analysis of SNP/haplotype frequencies in the cases and controls. Population substructure was evaluated by genotyping of 34 microsatellites. RESULTS: Twenty-five SNPs were detected across the three HSP70 genes. Analyses revealed that alleles G, T and C at the SNPs HSPA1A +1911 C/G, HSPA1A +438 C/T and HSPA1L +2437 T/C, respectively, were associated with protection from serious hypersensitivity reactions to CBZ, with the associated alleles falling on a common haplotype. We were unable to detect the presence of population stratification in our patients and controls. CONCLUSIONS: Our data show that HSP70 gene variants are associated with serious CBZ hypersensitivity reactions, but whether this is causal or reflects LD with another gene within the MHC requires further study.