Two siblings aged 5 and 15 years from Connecticut were hospitalized with petechial rash, oral mucositis, and severe thrombocytopenia approximately 10 days after they played with a jar of elemental mercury they found in their home. Before the mercury exposure was disclosed, the siblings were treated with platelet transfusions, intravenous immune globulin (IVIG) for possible immune thrombocytopenic purpura, and antibiotics for possible infectious causes. When their conditions did not improve after 6 days, poison control facilitated further questioning about toxic exposures including mercury, testing for mercury, and chelation with dimercaptosuccinic acid. The older sibling soon recovered, but the younger child required a prolonged hospitalization for severe thrombocytopenia, ultimately receiving repeated doses of IVIG, steroids, and romiplostim, a thrombopoietin receptor agonist. Close collaboration among multiple agencies was required to identify the extent of mercury contamination, evaluate and treat the other family members, and decontaminate the home. These cases demonstrate the importance of ongoing public health outreach to promote early detection of elemental mercury toxicity, and the need to evaluate for environmental exposures when multiple close contacts experience similar signs and symptoms.

Congenital cytomegalovirus (cCMV) infection is the leading nongenetic cause of sensorineural hearing loss (SNHL) in children.1 In the United States, cCMV occurs in an estimated 5 per 1000 live births.1 However, most cCMV infections remain undiagnosed. Newborns are usually tested for cCMV because of abnormal prenatal ultrasound findings, clinical suspicion at birth, maternal history of CMV infection during pregnancy, or referral from newborn hearing screening. Approximately 10% of infected infants present with clinical findings, such as purpura, petechiae, jaundice, hepatosplenomegaly, retinitis, or microcephaly, at birth.1 Up to 50% of symptomatic infants and 15% of asymptomatic infants present with SNHL either at birth or with delayed onset, which can be stable, fluctuating, or progressive.1

BACKGROUND: Long-term persistence of Ebola virus (EBOV) in immunologically-privileged sites has been implicated in recent outbreaks of Ebola Virus Disease (EVD) in Guinea and the Democratic Republic of Congo. This study was designed to understand how the acute course of EVD, convalescence, and host immune and genetic factors may play a role in prolonged viral persistence in semen. METHODS: A cohort of 131 male EVD survivors in Liberia were enrolled in a case-case study. "Early clearers" were defined as those with two consecutive negative EBOV semen tests by real-time reverse transcriptase polymerase chain reaction (rRT-PCR) at least two weeks apart within 1 year after discharge from the Ebola Treatment Unit (ETU) or acute EVD. "Late clearers" had detectable EBOV RNA by rRT-PCR over one year following ETU discharge or acute EVD. Retrospective histories of their EVD clinical course were collected by questionnaire, followed by complete physical exams and blood work. RESULTS: Compared to early clearers, late clearers were older (median 42.5 years, p = 0.0001) and experienced fewer severe clinical symptoms (median 2, p = 0.006). Late clearers had more lens opacifications (OR 3.9, 95%CI 1.1-13.3, p = 0.03), after accounting for age, higher total serum IgG3 titers (p = 0.007) and increased expression of the HLA-C*03:04 allele (OR 0.14, 95% CI 0.02-0.70, p = 0.007). CONCLUSIONS: Older age, decreased illness severity, elevated total serum IgG3 and HLA-C*03:04 allele expression may be risk factors for the persistence of EBOV in the semen of EVD survivors. EBOV persistence in semen may also be associated with its persistence in other immunologically protected sites, such as the eye.

BACKGROUND: The COVID-19 pandemic caused an abrupt drop in in-person health care (inpatient, Emergency Department, outpatient) and an increase in telehealth care, which poses challenges in vaccine safety studies that identify outcomes from in-person encounters. We examined the changes in incidence rates of selected encounter-based outcomes during the COVID-19 pandemic. METHODS: We assembled a cohort of members from 8 Vaccine Safety Datalink sites from January 1, 2017 through December 31, 2020. Using ICD-10 diagnosis codes or laboratory criteria, we identified 21 incident outcomes in traditional in-person settings and all settings. We defined 4 periods in 2020: January-February (pre-pandemic), April-June (early pandemic), July-September (middle pandemic), and October-December (late pandemic). We defined four corresponding periods in each year during 2017-2019. We calculated incidence rates, conducted difference in difference (DiD) analyses, and reported ratios of incidence rate ratios (RRR) to examine changes in rates from pre-pandemic to early, middle, and late pandemic in 2020, after adjusting for changes across similar periods in 2017-2019. RESULTS: Among>10 million members, regardless of setting and after adjusting for changes during 2017-2019, we found that incidence rates of acute disseminated encephalomyelitis, encephalitis/myelitis/encephalomyelitis/meningoencephalitis, and thrombotic thrombocytopenic purpura did not significantly change from the pre-pandemic to early, middle or late pandemic periods (p-values0.05). Incidence rates decreased from the pre-pandemic to early pandemic period during 2020 for acute myocardial infarction, anaphylaxis, appendicitis, Bell's palsy, convulsions/seizures, Guillain-Barr syndrome, immune thrombocytopenia (ITP), narcolepsy/cataplexy, hemorrhagic stroke, ischemic stroke, and venous thromboembolism (p-values<0.05). Incidence rates of Bell's palsy, ITP, and narcolepsy/cataplexy were higher in all settings than in traditional in-person settings during the three pandemic periods (p-values<0.05). CONCLUSION: Rates of some clinical outcomes during the pandemic changed and should not be used as historical background rates in vaccine safety studies. Inclusion of telehealth visits should be considered for vaccine studies involving Bell's palsy, ITP, and narcolepsy/cataplexy.

Among adults hospitalized for severe illness with probable MIS-A, 6 patients with hyperinflammation had mucocutaneous involvement, most commonly with purpura.

INTRODUCTION: Ebola virus (EBOV), species Zaire ebolavirus, may persist in the semen of male survivors of Ebola Virus Disease (EVD). We conducted a study of male survivors of the 2014-2016 EVD outbreak in Liberia and evaluated their immune responses to EBOV. We report here findings from the serologic testing of blood for EBOV-specific antibodies, molecular testing for EBOV in blood and semen, and serologic testing of peripheral blood mononuclear cells (PBMCs) in a subset of study participants. METHODS: We tested for EBOV RNA in blood by qRT-PCR, and for anti-EBOV-specific IgM and IgG antibodies by enzyme-linked immunosorbent assay (ELISA) for 126 study participants. We performed peripheral blood mononuclear cell (PBMC) analysis on a subgroup of 26 IgG-negative participants. RESULTS: All 126 participants tested negative for EBOV RNA in blood by qRT-PCR. The blood of 26 participants tested negative for EBOV-specific IgG antibodies by ELISA. PBMCs were collected from 23/26 EBOV IgG-negative participants. Of these, 1/23 participants had PBMCs which produced anti-EBOV-specific IgG antibodies upon stimulation with EBOV-specific GP and NP antigens. DISCUSSION: The blood of EVD survivors, collected when they did not have symptoms meeting the case definition for acute or relapsed EVD, is unlikely to pose a risk for EBOV transmission. We identified one IgM/IgG negative participant who had PBMCs which produced anti-EBOV-specific antibodies upon stimulation. Immunogenicity following acute EBOV infection may exist along a spectrum and absence of antibody response should not be exclusionary in determining an individual's status as a survivor of EVD.

BACKGROUND: During 2017, a multi-state outbreak investigation occurred following the confirmation of Seoul virus (SEOV) infections in people and pet rats. A total of 147 humans and 897 rats were tested. METHODS: In addition to IgG and IgM serology and traditional RT-PCR, novel quantitative RT-PCR primers/probe were developed, and whole genome sequencing was performed. RESULTS: Seventeen people had SEOV IgM, indicating recent infection; seven reported symptoms and three were hospitalized. All patients recovered. Thirty-one facilities in 11 US states had SEOV infection, and among those with >/=10 rats tested, rat IgG prevalence ranged 2-70% and SEOV RT-PCR positivity ranged 0-70%. Human lab-confirmed cases were significantly associated with rat IgG positivity and RT-PCR positivity (p=0.03 and p=0.006, respectively). Genomic sequencing identified >99.5% homology between SEOV sequences in this outbreak, and these were >99% identical to SEOV associated with previous pet rat infections in England, the Netherlands, and France. Frequent trade of rats between home-based ratteries contributed to transmission of SEOV between facilities. CONCLUSIONS: Pet rat owners, breeders, and the healthcare and public health community should be aware and take steps to prevent SEOV transmission in pet rats and to humans. Biosecurity measures and diagnostic testing can prevent further infections.

Purpura fulminans (PF) is a rare life-threatening complication of bacterial sepsis that is characterized by a highly thrombotic subtype of disseminated intravascular coagulation (DIC) and mortality of up to 80%.1 Patients with PF develop a severe deficiency in protein C (PC), a serine protease that is a key endogenous anticoagulant.2 PC is activated at the endothelial surface by thrombin in the presence of the cofactor thrombomodulin (TM). Activated PC (APC) is cytoprotective3 and inhibits thrombin generation by cleaving coagulation factors Va and VIIIa.4 Therefore, TM is a crucial regulatory “switch” governing negative feedback of coagulation. The initiating event in PF is hypothesized to be loss of TM from the endothelial surface in response to infection.5 As a result, conversion of PC to APC is impaired, and coagulation proceeds unchecked.3 Although therapy with PC concentrate has been proposed as a strategy to target the underlying pathophysiologic lesion in PF,6 the belief that endothelial TM loss is an early event in PF that renders infused PC ineffective has limited its widespread adoption.2,5 We report herein data on the kinetics of TM loss in a patient with PF that support the use of supplemental PC in upfront treatment of severe cases.

BACKGROUND: Rift Valley fever (RVF) is a zoonotic disease caused by Rift Valley fever virus (RVFV) found in Africa and the Middle East. Outbreaks can cause extensive morbidity and mortality in humans and livestock. Following the diagnosis of two acute human RVF cases in Kabale district, Uganda, we conducted a serosurvey to estimate RVFV seroprevalence in humans and livestock and to identify associated risk factors. METHODS: Humans and animals at abattoirs and villages in Kabale district were sampled. Persons were interviewed about RVFV exposure risk factors. Human blood was tested for anti-RVFV IgM and IgG, and animal blood for anti-RVFV IgG. PRINCIPAL FINDINGS: 655 human and 1051 animal blood samples were collected. Anti-RVFV IgG was detected in 78 (12%) human samples; 3 human samples (0.5%) had detectable IgM only, and 7 (1%) had both IgM and IgG. Of the 10 IgM-positive persons, 2 samples were positive for RVFV by PCR, confirming recent infection. Odds of RVFV seropositivity were greater in participants who were butchers (odds ratio [OR] 5.1; 95% confidence interval [95% CI]: 1.7-15.1) and those who reported handling raw meat (OR 3.4; 95% CI 1.2-9.8). No persons under age 20 were RVFV seropositive. The overall animal seropositivity was 13%, with 27% of cattle, 7% of goats, and 4% of sheep seropositive. In a multivariate logistic regression, cattle species (OR 9.1; 95% CI 4.1-20.5), adult age (OR 3.0; 95% CI 1.6-5.6), and female sex (OR 2.1; 95%CI 1.0-4.3) were significantly associated with animal seropositivity. Individual human seropositivity was significantly associated with animal seropositivity by subcounty after adjusting for sex, age, and occupation (p < 0.05). CONCLUSIONS: Although no RVF cases had been detected in Uganda from 1968 to March 2016, our study suggests that RVFV has been circulating undetected in both humans and animals living in and around Kabale district. RVFV seropositivity in humans was associated with occupation, suggesting that the primary mode of RVFV transmission to humans in Kabale district could be through contact with animal blood or body fluids.

BACKGROUND: Rift Valley Fever virus (RVF) is a zoonotic virus in the Phenuiviridae family. RVF outbreaks can cause significant morbidity and mortality in humans and animals. Following the diagnosis of two RVF cases in March 2016 in southern Kabale district, Uganda, we conducted a knowledge, attitudes and practice (KAP) survey to identify knowledge gaps and at-risk behaviors related to RVF. METHODOLOGY/PRINCIPAL FINDINGS: A multidisciplinary team interviewed 657 community members, including abattoir workers, in and around Kabale District, Uganda. Most participants (90%) had knowledge of RVF and most (77%) cited radio as their primary information source. Greater proportions of farmers (68%), herdsmen (79%) and butchers (88%) thought they were at risk of contracting RVF compared to persons in other occupations (60%, p<0.01). Participants most frequently identified bleeding as a symptom of RVF. Less than half of all participants reported fever, vomiting, and diarrhea as common RVF symptoms in either humans or animals. The level of knowledge about human RVF symptoms did not vary by occupation; however more farmers and butchers (36% and 51%, respectively) had knowledge of RVF symptoms in animals compared to those in other occupations (30%, p<0.01). The use of personal protective equipment (PPE) when handling animals varied by occupation, with 77% of butchers using some PPE and 12% of farmers using PPE. Although most butchers said that they used PPE, most used gumboots (73%) and aprons (60%) and less than 20% of butchers used gloves or eye protection when slaughtering. CONCLUSIONS: Overall, knowledge, attitudes and practice regarding RVF in Kabale District Uganda could be improved through educational efforts targeting specific populations.

Ebola virus is known to persist in semen of male survivors of Ebola virus disease (EVD). However, maximum duration of, or risk factors for, virus persistence are unknown. We report an EVD survivor with preexisting HIV infection, whose semen was positive for Ebola virus RNA 565 days after recovery from EVD.

On March 9, 2016, a male butcher from Kabale District, Uganda, aged 45 years, reported to the Kabale Regional Referral Hospital with fever, fatigue, and headache associated with black tarry stools and bleeding from the nose. One day later, a student aged 16 years from a different sub-county in Kabale District developed similar symptoms and was admitted to the same hospital. The student also had a history of contact with livestock. Blood specimens collected from both patients were sent for testing for Marburg virus disease, Ebola virus disease, Rift Valley fever (RVF), and Crimean Congo Hemorrhagic fever at the Uganda Virus Research Institute, as part of the viral hemorrhagic fevers surveillance program. The Uganda Virus Research Institute serves as the national viral hemorrhagic fever reference laboratory and hosts the national surveillance program for viral hemorrhagic fevers, in collaboration with the CDC Viral Special Pathogens Branch and the Uganda Ministry of Health.

The largest Ebola virus disease epidemic in history, the 2014 west African outbreak, left more than 17 000 survivors. Previously, Ebola virus RNA has been detected in semen by RT-PCR up to 101 days and infectious particles via culture up to 82 days after illness onset.1 As such, all male survivors of Ebola virus disease were advised to abstain from sex or use condoms for 3 months after recovery. In May 2015, genomic and epidemiological data provided evidence of sexual transmission of Ebola virus from a Liberian man who had detectable virus RNA 199 days after illness onset.2 This led WHO to recommend semen testing for all male survivors or safe sex practices for at least 6 months after illness onset if semen testing is not available.3 More recently, ongoing semen testing programmes in west Africa and USA have detected virus RNA in semen up to 290 days after disease onset and up to 565 days after disease recovery.4, 5 | Like Ebola virus disease, Zika virus has been found to persist in semen—RT-PCR has identified presence of virus 93 days after symptom onset,5 as has virus isolation 24 days after.6 As with Ebola virus, reported sexual transmission of Zika virus has led to changes in recommendations for safe sex practices. Condom use is recommended for asymptomatic men for 8 weeks after return from an area with ongoing local Zika virus transmission, and for symptomatic men, use for 6 months after onset of symptoms is advised.7

According to World Health Organization (WHO) data, the Ebola virus disease (Ebola) outbreak that began in West Africa in 2014 has resulted in 28,603 cases and 11,301 deaths. In March 2015, epidemiologic investigation and genetic sequencing in Liberia implicated sexual transmission from a male Ebola survivor, with Ebola virus detected by reverse transcription-polymerase chain reaction (RT-PCR) 199 days after symptom onset, far exceeding the 101 days reported from an earlier Ebola outbreak. In response, WHO released interim guidelines recommending that all male survivors, in addition to receiving condoms and sexual risk reduction counseling at discharge from an Ebola treatment unit (ETU), be offered semen testing for Ebola virus RNA by RT-PCR 3 months after disease onset, and every month thereafter until two consecutive semen specimens collected at least 1 week apart test negative for Ebola virus RNA. Male Ebola survivors should also receive counseling to promote safe sexual practices until their semen twice tests negative. When these recommendations were released, testing of semen was not widely available in Liberia. Challenges in establishing and operating the first nationwide semen testing and counseling program for male Ebola survivors included securing sufficient resources for the program, managing a public health semen testing program in the context of ongoing research studies that were also collecting and screening semen, identification of adequate numbers of trained counselors and appropriate health communication messages for the program, overcoming Ebola survivor-associated stigma, identification and recruitment of male Ebola survivors, and operation of mobile teams.

BACKGROUND: Ebola virus has been detected in semen of Ebola virus disease survivors after recovery. Liberia's Men's Health Screening Program (MHSP) offers Ebola virus disease survivors semen testing for Ebola virus. We present preliminary results and behavioural outcomes from the first national semen testing programme for Ebola virus. METHODS: The MHSP operates out of three locations in Liberia: Redemption Hospital in Montserrado County, Phebe Hospital in Bong County, and Tellewoyan Hospital in Lofa County. Men aged 15 years and older who had an Ebola treatment unit discharge certificate are eligible for inclusion. Participants' semen samples were tested for Ebola virus RNA by real-time RT-PCR and participants received counselling on safe sexual practices. Participants graduated after receiving two consecutive negative semen tests. Counsellors collected information on sociodemographics and sexual behaviours using questionnaires administered at enrolment, follow up, and graduation visits. Because the programme is ongoing, data analysis was restricted to data obtained from July 7, 2015, to May 6, 2016. FINDINGS: As of May 6, 2016, 466 Ebola virus disease survivors had enrolled in the programme; real-time RT-PCR results were available from 429 participants. 38 participants (9%) produced at least one semen specimen that tested positive for Ebola virus RNA. Of these, 24 (63%) provided semen specimens that tested positive 12 months or longer after Ebola virus disease recovery. The longest interval between discharge from an Ebola treatment unit and collection of a positive semen sample was 565 days. Among participants who enrolled and provided specimens more than 90 days since their Ebola treatment unit discharge, men older than 40 years were more likely to have a semen sample test positive than were men aged 40 years or younger (p=0.0004). 84 (74%) of 113 participants who reported not using a condom at enrolment reported using condoms at their first follow-up visit (p<0.0001). 176 (46%) of 385 participants who reported being sexually active at enrolment reported abstinence at their follow-up visit (p<0.0001). INTERPRETATION: Duration of detection of Ebola virus RNA by real-time RT-PCR varies by individual and might be associated with age. By combining behavioural counselling and laboratory testing, the Men's Health Screening Program helps male Ebola virus disease survivors understand their individual risk and take appropriate measures to protect their sexual partners. FUNDING: World Health Organization and the US Centers for Disease Control and Prevention.

BACKGROUND AND OBJECTIVES: All measles-containing vaccines are associated with several types of adverse events, including seizure, fever, and immune thrombocytopenia purpura (ITP). Because the measles-mumps-rubella-varicella (MMRV) vaccine compared with the separate measles-mumps-rubella (MMR) and varicella (MMR + V) vaccine increases a toddler's risk for febrile seizures, we investigated whether MMRV is riskier than MMR + V and whether either vaccine elevates the risk for additional safety outcomes. METHODS: Study children were aged 12 to 23 months in the Vaccine Safety Datalink from 2000 to 2012. Nine study outcomes were investigated: 7 main outcomes (anaphylaxis, ITP, ataxia, arthritis, meningitis/encephalitis, acute disseminated encephalomyelitis, and Kawasaki disease), seizure, and fever. Comparing MMRV with MMR + V, relative risk was estimated by using stratified exact binomial tests. Secondary analyses examined post-MMRV or MMR + V risk versus comparison intervals; risk and comparison intervals were then contrasted for MMRV versus MMR+V. RESULTS: We evaluated 123 200 MMRV and 584 987 MMR + V doses. Comparing MMRV with MMR + V, risks for the 7 main outcomes were not significantly different. Several outcomes had few or zero postvaccination events. Comparing risk versus comparison intervals, ITP risk was higher after MMRV (odds ratio [OR]: 11.3 [95% confidence interval (CI): 1.9 to 68.2]) and MMR + V (OR: 10 [95% CI: 4.5 to 22.5]) and ataxia risk was lower after both vaccines (MMRV OR: 0.8 [95% CI: 0.5 to 1]; MMR + V OR: 0.8 [95% CI: 0.7 to 0.9]). Compared with MMR + V, MMRV increased risk of seizure and fever 7 to 10 days after vaccination. CONCLUSIONS: This study did not identify any new safety concerns comparing MMRV with MMR + V or after either the MMRV or the MMR + V vaccine. This study provides reassurance that these outcomes are unlikely after either vaccine.

OBJECTIVE: This study assessed the risk of venous thromboembolism (VTE) among privately insured adults in the U.S. with one or more of the following autoimmune diseases: autoimmune hemolytic anemia (AIHA), immune thrombocytopenic purpura (ITP), rheumatoid arthritis (RA), and systemic lupus erythematosus (SLE). MATERIALS AND METHODS: Using the Truven Health MarketScan(R) Databases, patients 18-64 years of age with a diagnosis of AIHA, ITP, RA, or SLE in 2007 and a sex and age-group matched comparison group of enrollees were followed up through 2010 to identify VTE events. Survival curve and Cox proportional hazards analyses were conducted to assess differences between groups. RESULTS: Among patients with AIHA, ITP, RA, or SLE, or >1 of these diseases, the risk of at least one VTE event was 19.74, 7.72, 4.90, 9.89, and 13.35 per 1,000 person-years, respectively; among the comparison group, the risk was 1.91 per 1,000 person-years. The adjusted hazard ratios (aHRs) for VTE among patients with AIHA, ITP, RA, or SLE, or >1 of these diseases (when compared with the comparison group) tended to decline over follow-up time; at 1year, the aHRs were 6.30 (95% confidence interval [CI]: 4.44-8.94), 2.95 (95% CI: 2.18-4.00), 2.13 (95% CI: 1.89-2.40), 4.68 (95% CI: 4.10-5.33), and 5.11 (95% CI: 4.26-6.14), respectively. CONCLUSION: Having AIHA, ITP, RA, or SLE, or >1 of these diseases was associated with an increased likelihood of a VTE event. More research is necessary to develop better understanding of VTE occurrence among people with autoimmune diseases.

Previous research has suggested autoimmune diseases are risk factors for developing venous thromboembolism (VTE). We assessed whether having diagnoses of selected autoimmune diseases associated with antiphospholipid antibodies-autoimmune hemolytic anemia (AIHA), immune thrombocytopenic purpura (ITP), rheumatoid arthritis (RA), and systemic lupus erythematosus (SLE)-were associated with having a VTE diagnosis among US adult hospitalizations. A cross-sectional study was conducted using the 2010 Nationwide Inpatient Sample of the Healthcare Cost and Utilization Project, Agency for Healthcare Research and Quality. VTE and autoimmune diseases were identified using International Classification of Diseases, Ninth Revision, Clinical Modification coded diagnoses information. The percentages of hospitalizations with a VTE diagnosis among all non-maternal adult hospitalizations without any of the four autoimmune diseases of interest and among those with AIHA, ITP, RA, and SLE diagnoses were 2.28, 4.46, 3.35, 2.65 and 2.77 %, respectively. The adjusted odds ratios (OR) for having a diagnosis of VTE among non-maternal adult hospitalizations with diagnoses of AIHA, ITP, RA, and SLE were 1.25 [95 % confidence interval (CI) 1.05-1.49], 1.20 (95 % CI 1.07-1.34), 1.17 (95 % CI 1.13-1.21), and 1.23 (95 % CI 1.15-1.32), respectively, when compared to those without the corresponding conditions. The adjusted OR for a diagnosis of VTE associated with a diagnosis of any of the four autoimmune diseases was 1.20 (95 % CI 1.16-1.24). The presence of a diagnosis of AIHA, ITP, RA, and SLE was associated with an increased likelihood of having a VTE diagnosis among the group of all non-maternal adult hospitalizations.

SUMMARY: An outbreak of meningococcal disease (MD) with severe morbidity and mortality was investigated in midwestern Brazil in order to identify control measures. A MD case was defined as isolation of Neisseria meningitidis, or detection of polysaccharide antigen in a sterile site, or presence of clinical purpura fulminans, or an epidemiological link with a laboratory-confirmed case-patient, between June and August 2008. In 8 out of 16 MD cases studied, serogroup C ST103 complex was identified. Five (31%) cases had neurological findings and five (31%) died. The attack rate was 12 cases/100,000 town residents and 60 cases/100,000 employees in a large local food-processing plant. We conducted a matched case-control study of eight primary laboratory-confirmed cases (1:4). Factors associated with illness in single variable analysis were work at the processing plant [matched odds ratio (mOR) 22, 95% confidence interval (CI) 2.3-207.7, P<0.01], and residing <1 year in Rio Verde (mOR 7, 95% CI 1.11-43.9, P<0.02). Mass vaccination (>10 000 plant employees) stopped propagation in the plant, but not in the larger community.

BACKGROUND: We describe here a case of Henoch-Schonlein purpura (HSP) that occurred 10 days after administration of the meningococcal polysaccharide vaccine and came to the attention of a Vaccine Safety Datalink (VSD) investigator (but did not occur in the VSD cohort). Periodic case reports have linked vaccines to HSP. OBJECTIVE: To better understand the potential risk for HSP after immunization with the meningococcal polysaccharide vaccine. PATIENTS AND METHODS: We studied the VSD cohort to estimate the 42-day postvaccination incidence rate of HSP in the VSD population 16 to 20 years of age. Electronic data from all 8 VSD sites were gathered. All subjects aged 16 to 20 years who received a meningococcal polysaccharide vaccine were followed for 42 days after that vaccination for evidence of HSP. Background rates were determined by examining all the nonexposed time of the same cohort. RESULTS: No cases of HSP were seen in the 42 days after 49,027 doses of meningococcal polysaccharide vaccine among the entire VSD adolescent and young adult population. The background incidence rate was 4.2 per 100,000 person-years. CONCLUSION: These data provide the strongest evidence so far that HSP is not associated with receipt of meningococcal polysaccharide vaccine in the 16- to 20-year age group.