Incidence of symptomatic Lyme borreliosis in nine European countries.

OBJECTIVES: To better understand the Lyme borreliosis (LB) burden in Europe, we aimed to estimate the incidence of symptomatic Borrelia burgdorferi sensu lato (Bbsl) infections after adjusting public health LB surveillance data for under-detection of symptomatic Bbsl infections. METHODS: Data from seroprevalence studies and estimates of the symptomatic proportion and duration of antibody detection in Bbsl-infected individuals, derived from reviews of the published literature, were used to adjust public health LB surveillance data to estimate the incidence of symptomatic Bbsl infection in nine European countries from 2018-2022. RESULTS: The prevalence of anti-Bbsl antibodies ranged from 2.3% in Romania to 9.4% in Germany. Under-detection multipliers varied across surveillance systems; using 10-year duration of antibody detection, multipliers were 2.4-10.5 in countries reporting all LB cases and 54.6-722.2 in countries reporting only Lyme neuroborreliosis cases. The incidence of symptomatic Bbsl infection adjusted for under-detection was highest in Finland, Germany, Norway, Poland, and Switzerland, intermediate in the Czech Republic and Denmark, and lowest in Ireland and Romania. CONCLUSIONS: Adjustment of LB surveillance for under-detection found a high incidence of symptomatic Bbsl infection in several European countries. Differences in LB surveillance systems should be considered when comparing surveillance data between countries and when estimating LB disease burden.

Risk factors for Lyme disease among residents of rural, suburban, and urban areas in the United States: A Case-Control Study.

lyme disease (LD) is the most common vector-borne disease in the United States, with 476,000 cases estimated each year. It is unclear how LD risk factors vary by residential setting. We conducted a case-control study on LD risk by rural, urban, and suburban residential settings. Individuals from 15 high-incidence states and the District of Columbia in the Optum Research Database were identified as cases (LD medical claim) or controls (no LD medical claim, matched by county of residence and census block group population density). Participants were surveyed about LD history, outdoor activities, and residential characteristics. The final analytic dataset had 750 LD cases and 965 controls. Residence in a rural setting had increased LD risk (OR 1.41, 95% CI 1.16, 1.72). In multivariable analyses, activities associated with LD were hiking/walking/running or having an occupation in forests, wooded areas, or areas of tall grass (all respondents), and spending time in a yard (rural and urban residents only). Public health interventions can help prevent LD in high-incidence jurisdictions by reinforcing the nearuniversal LD risk for rural residents, and highlighting activities that lead to increased LD risk for those in areas with less ubiquitous tick exposure like in urban and suburban settings.

Incidence of symptomatic Borrelia burgdorferi sensu lato infection in Romania, 2018-2023.

BACKGROUND: Lyme borreliosis (LB), caused by Borrelia burgdorferi sensu lato (Bbsl), is the most common tick-borne disease in Europe. Although public health surveillance for LB has been conducted in Romania since 2007, the extent of under-detection of Bbsl infections by LB surveillance has not been estimated. We therefore estimated the under-detection of symptomatic Bbsl infections by LB surveillance to better understand the LB burden in Romania. METHODS: The number of incident symptomatic Bbsl infections were estimated from a seroprevalence study conducted in six counties (population 2.3 M) and estimates of the symptomatic proportion and duration of persistence of anti-Bbsl immunoglobulin G (IgG) antibodies. The number of incident symptomatic Bbsl infections were compared with the number of surveillance-reported LB cases to derive an under-detection multiplier, and then the under-detection multiplier was applied to LB surveillance data to estimate the incidence of symptomatic Bbsl infection from 2018 to 2023. RESULTS: We estimate that there were 1968 individuals with incident symptomatic Bbsl infection in the six counties where the seroprevalence study was conducted in 2020, compared with the 187 surveillance-reported LB cases, resulting in an under-detection multiplier of 10.5 (i.e., for every surveillance-reported LB case, there were 10.5 symptomatic incident Bbsl infections). The incidence of symptomatic Bbsl infection in the six counties was 86.9/100,000 population in 2023, similar to the incidence in 2018-2020 (86.0) and higher than in 2021-2022 (40.3). CONCLUSIONS: There is a higher incidence of symptomatic Bbsl infection than is reported through public health surveillance for LB in Romania. Additional efforts are needed to strengthen disease prevention and address the important public health problem of LB.

Global Seroprevalence of Tick-Borne Encephalitis Antibodies in Humans, 1956-2022: A Literature Review and Meta-Analysis.

Despite the availability of tick-borne encephalitis (TBE) vaccines, the incidence of TBE is increasing. To understand the historical patterns of infection, we conducted a global meta-analysis of studies before December 2023 reporting human antibody prevalence against TBEV (TBE virus) among general or high-risk population groups stratified by country, collection year, serological method, and vaccination status. Pooled data were compared within groups over time by random-effects modeling. In total, 2403 articles were retrieved; 130 articles published since 1959 were included. Data were extracted from 96 general populations (117,620 participants) and 71 high-risk populations (53,986 participants) across 33 countries. Germany had the most population groups (21), and Poland had the most participants (44,688). Seven serological methods were used; conventional IgG/IgM ELISAs were the most common (44%). Four studies (1.7%) used NS1-ELISA serology. Between 1956-1991 and 1992-2022, anti-TBEV seroprevalence remained at ~2.75% across all population groups from "high-risk" areas (p = 0.458) but decreased within general populations (1.7% to 1%; p = 0.001) and high-risk populations (5.1% to 1.3%; p < 0.001), possibly due to differences in the study methodologies between periods. This global summary explores how serological methods can be used to assess TBE vaccination coverage and potential exposure to TBEV or measure TBE burden and highlights the need for standardized methodology when conducting TBE seroprevalence studies to compare across populations.

Publicly available surveillance data on tick-borne encephalitis in Europe, 2023.

The European Centre for Disease Prevention and Control (ECDC) defines a case of tick-borne encephalitis (TBE) as an infection by the TBE virus (TBEV) with clinical manifestations of central nervous system inflammation (e.g., meningitis, encephalitis). To better understand the TBE surveillance landscape, online searches were conducted to determine if cases of TBE, TBEV infection, acute meningitis or encephalitis, or viral meningitis or encephalitis were subject to statutory reporting in European countries in 2023. In countries with statutory reporting, notification responsibility and available information on surveillance-reported cases were determined. The number of TBE cases reported to ECDC were compared with the number of cases recorded in national surveillance reports. Of 44 countries of the Europe Region of the United Nations, 37 (84 %) mandated statutory reporting of cases of TBE, TBEV infection, or acute/viral meningitis/encephalitis. Twenty-six (87 %) of 30 countries with identified surveillance reports recorded TBE cases in 2020-2023. Of these countries, 17 (65 %) required TBE reporting by clinicians and laboratories, 5 (19 %) by clinicians only, and 4 (15 %) by laboratories only. Twenty-four countries reported on TBE cases to ECDC in 2020; however, surveillance for TBE in Europe is heterogeneous. Standardization of TBE surveillance would enhance the understanding of TBE disease burden in Europe.

Effectiveness of Vaccination Against Tick-Borne Encephalitis in the Czech Republic, 2018-2022.

Background: Tick-borne encephalitis (TBE) is caused by the tick-borne encephalitis virus (TBEV). TBEV infection can cause symptoms of central nervous system (CNS) inflammation and result in severe consequences including death. TBE is an increasing health threat in the Czech Republic and elsewhere in Europe. In 2020, 23% of 3734 TBE cases reported to the European Centre for Disease Prevention and Control were from the Czech Republic. TBE vaccination is universally recommended in the Czech Republic, but a full analysis of TBE vaccine effectiveness (VE) in the Czech Republic has not been published. Methods: TBE is a notifiable disease in the Czech Republic with mandatory reporting of cases (i.e., laboratory-confirmed TBEV infected patient with symptoms of CNS inflammation) and vaccination history to public health authorities. TBE VE was estimated using the screening method utilizing public health surveillance data from 2018 to 2022 and online household surveys of the general population on TBE vaccine uptake conducted in 2019-2022. Results: In 2018-2022, 3648 TBE cases were reported in the Czech Republic; 98.1% (3105/3166) of TBE cases with known vaccination history were unvaccinated. Among 42,671 persons surveyed from the general population who had known TBE vaccination history, 66.5% were unvaccinated. VE against TBE was 97.6% (95% confidence interval 95.7-98.7). When stratified by age group, VE was 97.1% (88.4-99.3) in 1-15 years of age, 97.9% (95.3-99.0) in 16-59 years of age, and 96.9% (90.5-99.0) in ≥60 years of age. TBE vaccination averted an estimated 1020 TBE cases in the Czech Republic from 2018 to 2022. Conclusions: This first published study with a full analysis of TBE VE in the Czech Republic showed that vaccination was highly effective for the prevention of TBE including in children, an age group with increasing TBE disease burden. Vaccination averted hundreds of TBE cases and hospitalizations despite the relatively low compliance with TBE vaccine recommendations. To prevent additional TBE cases in the Czech Republic, enhanced efforts to increase TBE vaccine uptake are needed.

Incidence of public health surveillance-reported Clostridioides difficile infections in thirteen countries worldwide: A narrative review.

Clostridioides difficile infection (CDI) is an important cause of morbidity and mortality worldwide. Data from public health surveillance systems are important for estimating country-level CDI burden. CDI surveillance can be population-based or hospital-based. Population-based surveillance results in overall estimates of CDI incidence (cases per 100,000 population-per-year), and hospital-based surveillance results in estimates of hospital-based CDI incidence (cases per 10,000 patient-days) or CDI admission rates (cases per 1,000 admissions). We sought to better understand temporal trends in CDI incidence reported in publicly available surveillance data worldwide and describe varying surveillance methods. We identified 13 countries in Europe, North America, and Oceania with publicly available population-based and/or hospital-based CDI surveillance data in online reports and/or dashboards. Additional countries in Europe, in particular, also conduct hospital-based CDI surveillance. Inconsistent CDI case definitions and surveillance approaches between countries limit the interpretability of multi-country comparisons. Nonetheless, publicly available CDI surveillance data enabled us to compare CDI incidence among countries with population-based and/or hospital-based surveillance systems and to describe trends in CDI incidence within countries over time. The highest CDI incidence is in the United States. While there have been recent declines in CDI incidence in all countries, the CDI burden remains high, and the need persists for CDI prevention strategies in communities and healthcare settings.

Borrelia burgdorferi sensu lato prevalence in Ixodes scapularis from Canada: A thirty-year summary and meta-analysis (1990-2020).

Borrelia burgdorferi sensu lato (Bb) are a complex of bacteria genospecies that can cause Lyme disease (LD) in humans after the bite of an infected Ixodes spp. vector tick. In Canada, incidence of LD is increasing in part due to the rapid geographic expansion of Ixodes scapularis across the southcentral and eastern provinces. To better understand temporal and spatial (provincial) prevalence of Bb infection of I. scapularis and how tick surveillance is utilized in Canada to assess LD risk, a literature review was conducted. Tick surveillance studies published between January 1975 to November 2023, that measured the prevalence of Bb in I. scapularis via "passive surveillance" from the public citizenry or "active surveillance" by drag or flag sampling of host-seeking ticks in Canada were included for review. Meta-analyses were conducted via random effects modeling. Forty-seven articles, yielding 26 passive and 28 active surveillance studies, met inclusion criteria. Mean durations of collection for I. scapularis were 2.1 years in active surveillance studies (1999-2020) and 5.5 years by passive surveillance studies (1990-2020). Collectively, data were extracted on 99,528 I. scapularis nymphs and adults collected between 1990-2020 across nine provinces, including Newfoundland & Labrador (33 ticks) and Alberta (208 ticks). More studies were conducted in Ontario (36) than any other province. Across nine provinces, the prevalence of Bb infection in I. scapularis collected by passive surveillance was 14.6% with the highest prevalence in Nova Scotia at 20.5% (minimum studies >1). Among host-seeking I. scapularis collected via active surveillance, Bb infection prevalence was 10.5% in nymphs, 31.9% in adults, and 23.8% across both life stages. Host-seeking I. scapularis nymphs and adults from Ontario had the highest Bb prevalence at 13.6% and 34.8%, respectively. Between 2007-2019, Bb infection prevalence in host-seeking I. scapularis was positively associated over time (p<0.001) which is concurrent with a ∼25-fold increase in the number of annually reported LD cases in Canada over the same period. The prevalence of Bb-infection in I. scapularis has rapidly increased over three decades as reported by tick surveillance studies in Canada which coincides with increasing human incidence for LD. The wide-ranging distribution and variable prevalence of Bb-infected I. scapularis ticks across provinces demonstrates the growing need for long-term standardized tick surveillance to monitor the changing trends in I. scapularis populations and best define LD risk areas in Canada.

The burden of Clostridioides difficile infections in South-East Asia and the Western Pacific: A narrative review.

BACKGROUND: Clostridioides difficile (formerly Clostridium difficile) is well-documented in Europe and North America to be a common cause of healthcare-associated gastrointestinal tract infections. In contrast, C difficile infection (CDI) is infrequently reported in literature from Asia, which may reflect a lack of clinician awareness. We conducted a narrative review to better understand CDI burden in Asia. METHODS: We searched the PubMed database for English language articles related to C difficile, Asia, epidemiology, and molecular characteristics (eg, ribotype, antimicrobial resistance). RESULTS: Fifty-eight articles that met eligibility criteria were included. C difficile prevalence ranged from 7.1% to 45.1 % of hospitalized patients with diarrhea, and toxigenic strains among all C difficile in these patients ranged from 68.2% to 91.9 % in China and from 39.0% to 60.0 % outside of China. Widespread C difficile ribotypes were RT017, RT014/020, RT012, and RT002. Recurrence in patients with CDI ranged from 3.0% to 17.2 %. Patients with CDI typically had prior antimicrobial use recently. High rates of resistance to ciprofloxacin, clindamycin, and erythromycin were frequently reported. CONCLUSION: The regional CDI burden in Asia is still incompletely documented, seemingly due to low awareness and limited laboratory testing. Despite this apparent under recognition, the current CDI burden highlights the need for broader surveillance and for application of preventative measures against CDI in Asia.

Incidence of Lyme Borreliosis in Germany: A retrospective observational healthcare claims study.

Lyme borreliosis (LB) is the most common tick-borne disease in Germany. Although the incidence of LB in Germany has been assessed in several studies, those studies either used data from statutory surveillance, which frequently underreport cases, or data from health claims databases, which may overestimate cases due to non-specific LB case definitions. Here, using a more specific case definition, we describe the incidence of medically-attended LB by disease manifestation, age group, and federal state for the period 2015-2019. Both inpatient and outpatient cases were analyzed from a claims database. To be eligible for inclusion, patients were required to have an LB specific ICD-10 GM diagnosis code plus an antibiotic prescription, and for disseminated manifestations, a laboratory test order additionally. LB cases were classified as erythema migrans (EM), or disseminated disease including Lyme arthritis (LA), Lyme neuroborreliosis (LNB), and all other disease manifestations (OTH). Between 2015 and 2019, the incidence of medically-attended LB cases ranged from 195.7/100,000 population per year (95% confidence interval [CI], 191.0 - 200.5) to 254.5/100,000 population per year (95% CI, 249.0 - 260.0) per year. The majority of cases (92.2%) were EM, while 2.8% presented as LA, 3.8% as LNB, and 1.2% as OTH. For both EM and disseminated disease, the incidence peaked in children aged 5-9 years and in older adults. By federal state, the incidence of medically-attended EM ranged from 74.4/100,000 population per year (95% CI, 71.9 - 77.0) per year in Hamburg, to 394.1/100,000 population per year (95% CI, 370.7 - 417.6) per year in Saxony, whereas for medically-attended disseminated disease, the highest incidence was in Thuringia, Saxony, and Bavaria (range: 22.0 [95% CI, 19.9 - 24.0] to 35.7 [95% CI, 34.7 - 36.7] per 100,000 population per year). This study comprehensively estimated the incidence of all manifestations of medically-attended LB and showed a high incidence of LB throughout Germany. Results from the study support performing epidemiological studies in all federal states to measure the burden of LB and to invest in public health interventions for prevention.

Burden of Medically Attended Diarrhea and Outpatient Clostridioides difficile Infection Among Persons in 2 Large Integrated Healthcare Settings, 2016-2021.

Background: Identification of Clostridioides difficile infection (CDI) in the community setting is increasing. We describe testing for CDI among patients with medically attended diarrhea (MAD) in the outpatient setting, and the incidence of outpatient CDI. Methods: This was a retrospective cohort study among members ≥18 years of age from Kaiser Permanente Southern California and Kaiser Permanente Northwest from 1 January 2016 through 31 December 2021. MAD was identified by outpatient diarrheal International Classification of Diseases, Tenth Revision diagnosis codes, and CDI through positive laboratory results. Outpatient CDI was defined by no hospitalization ≤7 days after specimen collection. Incidence rates (IRs) of outpatient CDI were stratified by select demographic and clinical variables. Outpatient CDI burden 12 months following index date was measured by CDI-associated healthcare visits, and CDI testing and treatment. Results: We identified 777 533 MAD episodes; 12.1% (93 964/777 533) were tested for CDI. Of those tested, 10.8% (10 110/93 964) were positive. Outpatient CDI IR was 51.0 (95% confidence interval [CI], 49.8-52.2) per 100 000 person-years, decreasing from 58.2 (95% CI, 55.7-60.7) in 2016 to 45.7 (95% CI, 43.7-47.8) in 2021. Approximately 44% (n = 4200) received an antibiotic 30 days prior to index date and 84.1% (n = 8006) CDIs were "community-associated" (no hospitalizations 12 weeks prior to index date). Of outpatient CDIs, 6.7% (n = 526) had a CDI-associated hospitalization ≤12 months. Conclusions: There was a high incidence of outpatient CDI despite infrequent CDI testing among patients with MAD. The majority of those with outpatient CDI had no recent antibiotic use and no recent hospitalization. Further studies are needed to understand the source and management of medically attended outpatient CDI.

A systematic literature review of the effectiveness of tick-borne encephalitis vaccines in Europe.

BACKGROUND: Tick-borne encephalitis (TBE) is an infectious disease caused by the tick-borne encephalitis virus (TBEV) in patients with symptoms of central nervous system (CNS) inflammation. More than 25 European countries have one or more TBE-endemic areas. Although two TBE vaccines, FSME-IMMUN® and Encepur®, are commonly used in Europe, there are no published reviews of the real-world effectiveness of TBE vaccines in Europe or elsewhere. METHODS: We searched PubMed for TBE vaccine effectiveness (VE) articles and extracted information on country, study design, study period, study population, number of TBEV-infected cases, number of participants, and VE against TBEV infection and outcomes. RESULTS: We identified 13 studies, conducted in Austria, the Czech Republic, Latvia, Germany, and Switzerland, published in 2003-2023. One study was a cohort investigation of a milk-borne outbreak. In the other studies, 11 (91.7%) used the screening method and two (16.7%) used a case-control design (one study used both). TBE vaccines were highly effective (VE estimates >92%) against TBEV infection in all age groups. Vaccines were also highly protective against mild infections (i.e., infections in patients without symptoms of CNS inflammation), and against infections resulting in TBE and hospitalization. Vaccines were also highly protective against the most serious outcomes such as hospitalization greater than 12 days. Product-specific VE estimates were also high, though limited data were available. Studies in Austria, the Czech Republic, Latvia, and Switzerland estimated that TBE vaccines prevented >1,000 TBE cases a year, avoiding many hospitalizations and deaths, in these countries combined. CONCLUSIONS: Published VE studies demonstrate a high real-world effectiveness of the commercially available TBE vaccines in Europe. Although cases averted have been estimated in only four countries, TBE vaccination prevents thousands of cases in Europe each year. To prevent life-threatening TBE, TBE vaccine uptake and compliance with the vaccination schedule should be increased in residents of, and travelers to, TBE-endemic countries in Europe.

Estimated Incidence of Symptomatic Lyme Borreliosis Cases in Lublin, Poland in 2021.

Lyme borreliosis (LB), the most common tick-borne disease in Europe, is endemic to Poland. Despite public health surveillance with mandatory reporting of LB cases by physicians and laboratories, many symptomatic LB cases are not included in surveillance in Poland. We estimated the extent of the under-ascertainment of symptomatic LB cases via surveillance in the Polish province of Lublin to better understand Poland's LB burden. The number of incident symptomatic LB cases in Lublin in 2010 was estimated from two seroprevalence studies conducted among adults in Lublin, as well as estimates of the proportion of asymptomatic LB cases and the duration of LB antibody persistence. The estimated number of incident symptomatic LB cases was compared to the number of surveillance-reported cases in Lublin to derive an under-ascertainment multiplier. This multiplier was applied to the number of surveillance-reported cases in 2021 to estimate the number and population-based incidence of symptomatic LB cases in Lublin in 2021. We estimate that there are 5.9 symptomatic LB cases for every surveillance-reported LB case in Lublin. Adjusting for under-ascertainment, the estimated number of symptomatic LB cases in Lublin in 2021 was 6204 (population-based incidence: 467.6/100,000). After adjustment for under-ascertainment, the incidence of symptomatic LB in Lublin, Poland, is high.

First evidence of tick-borne encephalitis (TBE) outside of Hokkaido Island in Japan.

Tick-borne encephalitis (TBE) is an infection of the central nervous system caused by the tick-borne encephalitis virus (TBEV). TBE is endemic in parts of Europe and Asia. TBEV is transmitted to humans primarily by Ixodes ticks. There have been 5 TBE cases identified in Japan, all on the northern island of Hokkaido. Rodents with TBEV antibodies and Ixodes ticks have been identified throughout Japan, indicating that TBEV infection might be undiagnosed in Japan. Residual serum and cerebrospinal fluid (CSF) collected in 2010-2021 from 520 patients ≥1 year-of-age previously hospitalized with encephalitis or meningitis of unknown etiology at 15 hospitals (including 13 hospitals outside of Hokkaido) were screened by ELISA for TBEV IgG and IgM antibodies; TBEV infection was confirmed by the gold standard neutralization test. Residual serum was available from 331 (63.6%) patients and CSF from 430 (82.6%) patients; both serum and CSF were available from 189 (36.3%). Two patients were TBE cases: a female aged 61 years hospitalized for 104 days in Oita (2000 km south of Hokkaido) and a male aged 24 years hospitalized for 11 days in Tokyo (1200 km south of Hokkaido). Retrospective testing also identified a previous TBEV infection in a female aged 45 years hospitalized for 12 days in Okayama (1700 km south of Hokkaido). TBEV infection should be considered as a potential cause of encephalitis or meningitis in Japan. TBE cases are likely undiagnosed in Japan, including outside of Hokkaido, due to limited clinical awareness and lack of availability of TBE diagnostic tests.

The Incidence of Lyme Borreliosis Among Children.

BACKGROUND: First recognized in children in the United States, Lyme borreliosis (LB) is the most prevalent tickborne illness in North America and Europe. However, the incidence of LB in children, including geographic variation and difference from that in adults, is incompletely described. METHODS: We compiled surveillance data from public health agency websites reporting age-stratified LB case data, which was combined with census data to derive incidence estimates. Additional incidence estimates were obtained through a systematic literature review. RESULTS: We identified 18 surveillance systems and 15 published studies for derivation of LB incidence in children. National incidence of >10 cases in children per 100,000 per year were estimated for the United States and parts of Eastern, Western and Northern Europe. However, there was substantial variation in incidence among countries in some European regions. National incidence estimates from the literature largely aligned with estimates from surveillance. Surveillance-reported pediatric incidence was lower than adult incidence in adults in 8 countries, similar to adult incidence in 3 countries, and higher than adult incidence in 1 country. Among all pediatric age strata, the 5-9 years of age stratum had the highest proportion of pediatric cases in most countries. CONCLUSIONS: As pediatric LB represents a substantial proportion of overall LB incidence across countries in Europe and North America, LB prevention and control efforts should target pediatric as well as adult populations. However, better data are needed to fully characterize the difference in incidence across geographic regions.

Effectiveness of Tick-borne Encephalitis Vaccines in Children, Latvia, 2018-2020.

BACKGROUND: Tick-borne encephalitis (TBE) is an infection by the tick-borne encephalitis virus (TBEV) with symptoms of central nervous system inflammation. TBE is endemic in Latvia and other parts of Europe. TBE vaccination is recommended for children in Latvia. TBE vaccine effectiveness (VE) was estimated in Latvia, a country with high TBE incidence, providing the first VE estimates against a range of TBEV infection outcomes in children 1-15 years-of-age. METHODS: Riga Stradins University conducted nationwide surveillance for suspected TBE cases. Serum and cerebrospinal fluid were ELISA tested for TBEV-specific IgG and IgM antibodies. A fully vaccinated child was an individual who had received the 3-dose primary series and appropriately timed boosters. The proportion of laboratory-confirmed TBE cases fully vaccinated (PCV) was determined from interviews and medical records. The proportion of the general population fully vaccinated (PPV) was determined from national surveys conducted in 2019 and 2020. TBE VE in children 1-15 years-of-age was estimated using the screening method: VE = 1 - [PCV/(1 - PCV)/PPV/(1 - PPV)]. RESULTS: From 2018 to 2020, surveillance identified 36 TBE cases in children 1-15 years-of-age; all were hospitalized, 5 (13.9%) for >12 days. Of the TBE cases, 94.4% (34/36) were unvaccinated compared with 43.8% of children in the general population. VE against TBE hospitalization in children 1-15 years-of-age was 94.9% (95% confidence interval 63.1-99.3). In 2018-2020, vaccination in children 1-15 years-of-age averted 39 hospitalized TBE cases. CONCLUSION: Pediatric TBE vaccines were highly effective in preventing TBE in children. Increasing TBE vaccine uptake in children is essential to maximize the public health impact of TBE vaccination.

Effectiveness of tick-borne encephalitis vaccination in Latvia, 2018-2020: an observational study.

OBJECTIVES: Tick-borne encephalitis (TBE) is an infection by the tick-borne encephalitis virus (TBEV) that results in symptoms of central nervous system inflammation. TBE is endemic in Latvia and other European countries. TBE vaccines are commonly used in Latvia, but vaccine effectiveness estimates are limited. METHODS: Study staff at Riga Stradins University conducted nationwide active surveillance for TBEV infections. Serum and cerebrospinal fluid were ELISA-tested for TBEV-specific IgG and IgM antibodies. Vaccination history was collected by interview and medical record review. Utilizing data from surveillance and population surveys, vaccine effectiveness (with 95% CIs) and cases averted were estimated using the screening method. RESULTS: There were 587 laboratory-identified TBE cases from 2018 to 2020; 98.1% (576/587) were unvaccinated, 1.5% (9/587) were unknown or partially vaccinated, and 0.3% (2/587) were fully vaccinated (three-dose primary series and appropriately timed boosters). TBE resulted in the death of 1.7% (10/587) of TBE cases. TBE vaccine history was ascertained from 92.0% (13 247/14 399) people from the general population: 38.6% (5113/13 247) were unvaccinated, 26.3% (3484/13 247) were fully vaccinated, and 35.1% (4650/13 247) were partially vaccinated. TBE vaccine effectiveness was 99.5% (98.0-99.9) against TBE, 99.5% (97.9-99.9) against TBE hospitalization, 99.3% (94.8-99.9) against moderate/severe TBE, and 99.2% (94.4-99.9) against TBE hospitalization >12 days. From 2018 to 2020, vaccination averted 906 TBE cases, including 20 deaths. DISCUSSION: TBE vaccine was highly effective in preventing TBE, moderate and severe disease, and prolonged hospitalization. To prevent life-threatening TBE, TBE vaccine uptake and compliance should be increased in Latvia and other European regions where TBE is endemic.

The impact of COVID-19 vaccination in the US: Averted burden of SARS-COV-2-related cases, hospitalizations and deaths.

By August 1, 2022, the SARS-CoV-2 virus had caused over 90 million cases of COVID-19 and one million deaths in the United States. Since December 2020, SARS-CoV-2 vaccines have been a key component of US pandemic response; however, the impacts of vaccination are not easily quantified. Here, we use a dynamic county-scale metapopulation model to estimate the number of cases, hospitalizations, and deaths averted due to vaccination during the first six months of vaccine availability. We estimate that COVID-19 vaccination was associated with over 8 million fewer confirmed cases, over 120 thousand fewer deaths, and 700 thousand fewer hospitalizations during the first six months of the campaign.

Misdiagnosis of Clostridioides difficile Infections by Standard-of-Care Specimen Collection and Testing among Hospitalized Adults, Louisville, Kentucky, USA, 2019-20201.

Although Clostridioides difficile infection (CDI) incidence is high in the United States, standard-of-care (SOC) stool collection and testing practices might result in incidence overestimation or underestimation. We conducted diarrhea surveillance among inpatients >50 years of age in Louisville, Kentucky, USA, during October 14, 2019-October 13, 2020; concurrent SOC stool collection and CDI testing occurred independently. A study CDI case was nucleic acid amplification test‒/cytotoxicity neutralization assay‒positive or nucleic acid amplification test‒positive stool in a patient with pseudomembranous colitis. Study incidence was adjusted for hospitalization share and specimen collection rate and, in a sensitivity analysis, for diarrhea cases without study testing. SOC hospitalized CDI incidence was 121/100,000 population/year; study incidence was 154/100,000 population/year and, in sensitivity analysis, 202/100,000 population/year. Of 75 SOC CDI cases, 12 (16.0%) were not study diagnosed; of 109 study CDI cases, 44 (40.4%) were not SOC diagnosed. CDI incidence estimates based on SOC CDI testing are probably underestimated.