tbuckley/cabot-search huggingface dataset:
Reduced Ebola vaccine responses in CMV+ young adults is associated with expansion of CD57+KLRG1+ T cells
Authors: Georgina Bowyer, Hannah Sharpe, Navin Venkatraman, Pierre Birahim Ndiaye, Djibril Wade, Nicole Brenner, Alex Mentzer, Catherine Mair, Tim Waterboer, Teresa Lambe, Tandakha Dieye, Souleymane Mboup, Adrian V.S. Hill, Katie J. Ewer
Journal: The Journal of Experimental Medicine (2020)

CMV is associated with immunosenescence and reduced vaccine responses in the elderly (>70 yr). However, the impact of CMV in young adults is less clear. In this study, healthy UK and Senegalese adults aged 18-50 yr (average, 29 yr) were vaccinated with the Ebola vaccine candidate chimpanzee adenovirus type 3-vectored Ebola Zaire vaccine (ChAd3-EBO-Z) and boosted with modified vaccinia Ankara Ebola Zaire-vectored (MVA-EBO-Z) vaccine. CMV carriage was associated with an expansion of phenotypically senescent CD4+ and CD8+ T cells expressing CD57 and killer cell lectin-like receptor G1 (KLRG1), which was negatively associated with vaccine responses in both cohorts. Ebola-specific T cell responses induced by vaccination also contained significantly increased frequencies of terminally differentiated CD57+KLRG1+ cells in CMV seropositive (CMV+) individuals. This study suggests that CMV can also affect vaccine responses in younger adults and may have a particularly marked impact in many developing countries where CMV seroprevalence is almost universal.
SAT0516 CLINICAL FEATURE OF ACUTE RHEUMATIC FEVER AND POST-STREPTOCOCCAL REACTIVE ARTHRITIS
Authors: Satoshi Sato, Kenichi Yamaguchi, Masaaki Mori
Journal: Annals of the Rheumatic Diseases (2019)

<h3>Background:</h3> Acute Rheumatic Fever (ARF) and Post-streptococcal reactive arthritis (PSRA) are well known as post-streptococcal syndromes with arthritis in children. ARF have been declining in developed nations and it is generally thought to be a disease of the past. Despite decreasing incidence, focal outbreaks have been reported in developed nations. Despite its importance, ARF and PSRA epidemiology has not been reviewed recently. <h3>Objectives:</h3> The aims of this study were to assess ARF and PSRA incidence between 2010 and 2018 in Japan. <h3>Methods:</h3> This retrospective Study examined ARF and PSRA incidence in 2010-2018, using medical record included in a total of 108 hospitals. <h3>Results:</h3> From a total of 63 hospitals (58% response rate), 34 cases of ARF and 32 cases of PSRA were reported. The mean age of ARF was 8.0 years (3-15 years), and female/male ratio was 13/21. Manifestations including; carditis, 26 (78.8%); arthritis, 26 (78.8%); Erythema marginatum in 7 (21.2%); Sydenham chorea, 4 (12.1%); Subcutaneous nodules, 2 (6.1%), respectively. And minor criteria were; fever, 27 (81.8%); first degree heart block, 7 (21.2%); elevated inflammatory markers (ESR, CRP), 30 (90.9%). ARF patients were treated with antimicrobial agent therapy 33 (100%); NSAIDs 24 (72.7%); and glucocorticoids therapy 15 (45.4%). All ARF patients were prescribed with antimicrobial agent prophylaxis. On the other hand, the mean age of PSRA was 8.0 years (3-14 years), and female/male ratio was 17/14. Three patients (9.4%) had monoarthritis, 15 patients (46.9%) had oligoarthritis, and 14 patients (43.6%) had polyarthritis. Two patients had arthritis and enthesitis. And fever in 24 (75.0%) and Elevated inflammatory markers in 29 (90.6%). PSRA patients were treated with antimicrobial agent therapy 25 (78.1%); NSAIDs 27 (84.4%); and glucocorticoids therapy 3 (9.4%). During the follow up, there was no patient with carditis. 18 (56.3%) patients with PSRA were prescribed with antimicrobial agent prophylaxis. <h3>Conclusion:</h3> In this study, ARF is rare in the Japanese pediatric population, but ARF has not yet disappeared. We observed high incidence of arthritis, carditis and erythema marginatum. No PSRA case was complicated with carditis. General pediatrician need to have updated information about ARF and PSRA even in industrialized countries. <h3>References</h3> [1] Sato S, Uejima Y, Suganuma E, et al. A retrospective study: Acute rheumatic fever and post-streptococcal reactive arthritis in Japan. Allergol Int. 2017;66(4):617-620. <h3>Disclosure of Interests:</h3> None declared
GP who was suspended for forging out-of-hours form can resume work to assist in pandemic
Authors: Clare Dyer
Journal: BMJ (2020)

A GP who was suspended for forging his supervisor’s signature when he was a trainee may resume work under set conditions, after an emergency physician asked the Medical Practitioners Tribunal Service (MPTS) to let him help with the pandemic in hard pressed emergency and intensive care departments.

Joseph Smith was suspended for five months after a tribunal found last December that he had, “in January 2018, dishonestly completed an out-of-hours supervision form in the course of his work, then forged the signature of his supervisor on that form.”

That tribunal found, “This dishonesty was compounded by subsequent repeated denials. In his first …
Marked Disparity Between Trabecular and Cortical Bone Loss with Age in Healthy Men
Authors: Diane E. Meier, Eric S. Orwoll, James M. Jones
Journal: Annals of Internal Medicine (2020)

Abstract To define age-related changes in bone mineral content in normal men, we measured radial (proximal and distal) and vertebral bone mineral content in 62 men aged 30 to 92 years. Radial bone ...
ACQUIRED AND LOST DOUBLE PYLORUS: CLINICAL AND ENDOSCOPIC CHARACTERISTICS THROUGH FOURTEEN-MONTH FOLLOW-UP
Authors: V Milivojevic, S Sagdati, S Catovic, M Krstic, T Milosavljevic
Journal: Endoscopy (2020)

A double pylorus (DP) is a derived or acquired rare endoscopic finding characterized by the presence of two openings from the stomach antrum to the duodenal bulb.
Antigen-stimulated PBMC transcriptional protective signatures for malaria immunization
Authors: Gemma Moncunill, Anja Scholzen, Maximillian Mpina, Augusto Nhabomba, Aurore Bouyoukou Hounkpatin, Lourdes Osaba, Raquel Valls, Joseph J. Campo, Hèctor Sanz, Chenjerai Jairoce, Nana Aba Williams, Erica M. Pasini, David Arteta, Joan Maynou, Lourdes Palacios, Miquel Duran-Frigola, John J. Aponte, Clemens H. M. Kocken, Selidji Todagbe Agnandji, José Manuel Mas, Benjamin Mordmüller, Claudia Daubenberger, Robert Sauerwein, Carlota Dobaño
Journal: Science Translational Medicine (2020)

Identifying immune correlates of protection and mechanisms of immunity accelerates and streamlines the development of vaccines. RTS,S/AS01E, the most clinically advanced malaria vaccine, has moderate efficacy in African children. In contrast, immunization with sporozoites under antimalarial chemoprophylaxis (CPS immunization) can provide 100% sterile protection in naïve adults. We used systems biology approaches to identifying correlates of vaccine-induced immunity based on transcriptomes of peripheral blood mononuclear cells from individuals immunized with RTS,S/AS01E or chemoattenuated sporozoites stimulated with parasite antigens in vitro. Specifically, we used samples of individuals from two age cohorts and three African countries participating in an RTS,S/AS01E pediatric phase 3 trial and malaria-naïve individuals participating in a CPS trial. We identified both preimmunization and postimmunization transcriptomic signatures correlating with protection. Signatures were validated in independent children and infants from the RTS,S/AS01E phase 3 trial and individuals from an independent CPS trial with high accuracies (>70%). Transcription modules revealed interferon, NF-κB, Toll-like receptor (TLR), and monocyte-related signatures associated with protection. Preimmunization signatures suggest that priming the immune system before vaccination could potentially improve vaccine immunogenicity and efficacy. Last, signatures of protection could be useful to determine efficacy in clinical trials, accelerating vaccine candidate testing. Nevertheless, signatures should be tested more extensively across multiple cohorts and trials to demonstrate their universal predictive capacity.
MEDIASTINAL MASS AS A MELANOMA METASTASIS, AN UNUSUAL PRESENTATION
Authors: IO Usieto, BA Castillo, B Lanseros, MG Haba, JP Rojas Ortiz, CS Antón, JL Calleja Panero
Journal: Endoscopy (2020)

Aims We present a case of diagnosis of metastatic melanoma in the form of mediastinal mass, which debuts clinically with an Guillain Barré paraneoplastic syndrome.
UTILITY OF SHOCK INDEX FOR RISK STRATIFICATION IN ACUTE LOWER GASTROINTESTINAL BLEEDING
Authors: S Machlab, P Garcia - Iglesias, E Martinez-Bauer, P Pedregal, G Grau, M Raurich, S Marin, F Junquera, V Puig-Divi, X Calvet, R Campo, E Brullet
Journal: Endoscopy (2020)

Aims The aim of this study was compare the utility of Shock Index (SI) for predicting outcomes on acute lower gastrointestinal bleeding (LGB).
Permanent Endocardial Pacing in Complete Heart Block
Authors: J. Warren Harthorne, W. Gerald Austen, Howard Corning, Joseph J. Mcnamara, Charles A. Sanders
Journal: Annals of Internal Medicine (2020)

Excerpt The prevalence of symptomatic complete heart block is not known but appears to be increasing with prolongation of life expectancy. Heart block is one of the more common disorders of the hea...
Age And Sex Distribution Of Patients Presenting To Specialist Cough Clinics
Authors: A H Morice, A D Jakes, S Faruqi, S Birring, L McGarvey, B Canning, J A Smith, S Parker, K F Chung, Lai K-F., S Mazzone, I D Pavord, P Dicpinigaitis, C C Registry
Journal: American Journal of Respiratory and Critical Care Medicine (2013)
Reflections of a Millennial Surgeon
Authors: William Clifton
Journal: JAMA Surgery (2020)

Our website uses cookies to enhance your experience. By continuing to use our site, or clicking "Continue," you are agreeing to our Cookie Policy | Continue JAMA Surgery HomeNew OnlineCurrent IssueFor Authors Podcast Publications JAMA JAMA Network Open JAMA Cardiology JAMA Dermatology JAMA Health Forum JAMA Internal Medicine JAMA Neurology JAMA Oncology JAMA Ophthalmology JAMA Otolaryngology–Head & Neck Surgery JAMA Pediatrics JAMA Psychiatry JAMA Surgery Archives of Neurology & Psychiatry (1919-1959) JN Learning / CMESubscribeJobsInstitutions / LibrariansReprints & Permissions Terms of Use | Privacy Policy | Accessibility Statement 2023 American Medical Association. All Rights Reserved Search All JAMA JAMA Network Open JAMA Cardiology JAMA Dermatology JAMA Forum Archive JAMA Health Forum JAMA Internal Medicine JAMA Neurology JAMA Oncology JAMA Ophthalmology JAMA Otolaryngology–Head & Neck Surgery JAMA Pediatrics JAMA Psychiatry JAMA Surgery Archives of Neurology & Psychiatry Input Search Term Sign In Individual Sign In Sign inCreate an Account Access through your institution Sign In Purchase Options: Buy this article Rent this article Subscribe to the JAMA Surgery journal
A Randomized, Controlled Phase 3 Study, LIBERTY ASTHMA QUEST, Evaluating the Efficacy and Safety of Dupilumab in Uncontrolled Moderate-to-Severe Asthma
Authors: M Castro, J Corren, I D Pavord, J F Maspero, S E Wenzel, K F Rabe, W W Busse, L B Ford, L Sher, J FitzGerald, C Katelaris, Y Tohda, B Zhang, H Staudinger, G Pirozzi, N Amin, M Ruddy, B Akinlade, A Khan, J Chao, R Martincova, N M Graham, A Teper
Journal: American Journal of Respiratory and Critical Care Medicine (2018)
ENDOSCOPIC RETRIEVAL OF A BI-FLANGED METAL STENT RELEASED INTO A PERIPANCREATIC FLUID COLLECTION THROUGH A LUMEN-APPOSING METAL STENT
Authors: E Troncone, GDV Blanco, C Petruzziello, B Neri, M Mossa, G Monteleone, A Larghi
Journal: Endoscopy (2020)

A 16 mm bi-flanged metal stent (BFMS) was mistakenly released inside a peripancreatic fluid collection (PFC) during transgastric drainage. In an attempt to endoscopically retrieve the stent, the PFC was punctured under EUS with a 19 Gauge FNA needle and filled with normal saline. An electro-cautery enhanced 20 mm lumen-apposing metal stent (LAMS) was then placed under full EUS guidance and the middle portion balloon dilated up to 20 mm. This allowed introduction of a gastroscope through the LAMS into the cavity, where the dislocated BFMS was entrapped into a polypectomy retrieval net and safely extracted under direct endoscopic view.
Clinical Characteristics and Outcomes of Patients With Diabetes and COVID-19 in Association With Glucose-Lowering Medication
Authors: Yuchen Chen, Dong Yang, Biao Cheng, Jian Chen, Anlin Peng, Chen Yang, Chong Liu, Mingrui Xiong, Aiping Deng, Yu Zhang, Ling Zheng, Kun Huang
Journal: Diabetes Care (2020)

OBJECTIVE Diabetes is one of the most distinct comorbidities of COVID-19. Here, we describe the clinical characteristics of and outcomes in patients with diabetes in whom COVID-19 was confirmed or clinically diagnosed (with typical features on lung imaging and symptoms) and their association with glucose-lowering or blood pressure–lowering medications. RESEARCH DESIGN AND METHODS In this retrospective study involving 904 patients with COVID-19 (136 with diabetes, mostly type 2 diabetes), clinical and laboratory characteristics were collected and compared between the group with diabetes and the group without diabetes, and between groups taking different medications. Logistic regression was used to explore risk factors associated with mortality or poor prognosis. RESULTS The proportion of comorbid diabetes is similar between cases of confirmed and of clinically diagnosed COVID-19. Risk factors for higher mortality of patients with diabetes and COVID-19 were older age (adjusted odds ratio [aOR] 1.09 [95% CI 1.04, 1.15] per year increase; P = 0.001) and elevated C-reactive protein (aOR 1.12 [95% CI 1.00, 1.24]; P = 0.043). Insulin usage (aOR 3.58 [95% CI 1.37, 9.35]; P = 0.009) was associated with poor prognosis. Clinical outcomes of those who use an ACE inhibitor (ACEI) or angiotensin II type-I receptor blocker (ARB) were comparable with those of patients who do not use ACEI/ARB among COVID-19 patients with diabetes and hypertension. CONCLUSIONS C-reactive protein may help to identify patients with diabetes who are at greater risk of dying during hospitalization. Older patients with diabetes were prone to death related to COVID-19. Attention needs to be paid to patients with diabetes and COVID-19 who use insulin. ACEI/ARB use showed no significant impact on patients with diabetes and hypertension who have COVID-19.
FIRST TRIAL OF REVERSE PERORAL ENDOSCOPIC MYOTOMY FOR REFRACTORY BENIGN ESOPHAGEAL STRICTURE
Authors: YW Shin, W Ko
Journal: Endoscopy (2020)

Aims The most commonly implicated caustic agent is the alkali-sodium hypochlorite (lye: detergent). Benign strictures of the esophagus are presumed to be sequele of deep esophageal injury. Dilatation with bougies or balloons is the classic treatment for esophageal strictures. Kochman defined refractory benign esophageal stricture (RBES) as more than 3–5 dilations having been performed without clinical and endoscopic response. This report is believed to be the first trial of POEM on lye ingestion induced esophageal stricture.
Continuous positive airway pressure to avoid intubation in SARS-CoV-2 pneumonia: a two-period retrospective case-control study
Authors: Mathilde Oranger, Jésus Gonzalez-Bermejo, Philippine Dacosta-Noble, Claudia Llontop, Antoine Guerder, Valery Trosini-Desert, Morgane Faure, Mathieu Raux, Maxens Decavele, Alexandre Demoule, Capucine Morélot-Panzini, Thomas Similowski
Journal: European Respiratory Journal (2020)

<b>COVID-19 pneumonia can be life-threatening. Given the unprecedented burden placed on ICU resources by the epidemic, avoiding intubation is a major issue. This study suggests that CPAP can achieve this objective.</b>https://bit.ly/2X4Q8Zj
Covid-19: Pandemic exposes inequalities in global food systems
Authors: Jacqui Wise
Journal: BMJ (2020)

The coronavirus pandemic has exposed the vulnerability and weaknesses of already fragile global food systems, say the authors of a new report which finds one in every nine people in the world is hungry while one in three is overweight or obese.

The Global Nutrition Report 2020 calls on governments, businesses, and civil society to step up efforts to tackle malnutrition in all its forms, as well as injustices in food and health systems.1

The report found that an increasing number of countries experience the double burden of malnutrition, where undernutrition coexists with obesity …
Giving Pediatric Immunizations the Priority They Deserve
Authors: Donna E. Shalala
Journal: JAMA (1993)

In the first 6 months of 1991, a rubella outbreak struck a rural community in Pennsylvania, resulting in the births of at least 27 infants with congenital rubella syndrome. Until that time, the entire state had witnessed only two documented cases of congenital rubella syndrome in the previous 20 years—one in 1972 and one in 1975.<sup>1</sup>Unfortunately, when it comes to preventable childhood infectious diseases in the United States, this story is not unique. Today, between 37% and 56% of the 7.8 million 2-year-olds in America—about 4 million children— are not fully immunized (unpublished data, Centers for Disease Control and Prevention, 1991). These figures are alarming. Although the vaccines necessary to guard children against infectious diseases such as mumps, measles, diphtheria, hepatitis B, and polio are available, safe, and effective, we as a nation have failed to provide these immunizations on time. Clearly, protecting our See also p 1817.
COLON CAPSULE ENDOSCOPY (CCE) IS AN EFFECTIVE FILTER TEST FOR COLONIC POLYP SURVEILLANCE
Authors: S Semenov, T Manoharan, S Sihag, K Hazel, MS Ismail, D Molloy, B Ryan, N Breslin, A O’Connor, D McNamara
Journal: Endoscopy (2020)

Aims Surveillance accounts for 30% of colonoscopy workload, the majority are normal. Identifying patients who require polypectomy would be advantageous. We aimed to assess CCE and/or faecal immunochemical test (FIT) as a potential filter in surveillance.
Treatment of Non-Hodgkin's Lymphoma
Authors: Alastair J.J. Wood, James O. Armitage
Journal: New England Journal of Medicine (1993)

The disorders classified as non-Hodgkin's lymphoma are increasing in frequency in the United States, with more than 35,000 cases diagnosed annually. In recent years, there have been numerous advances in our understanding of the biology of these disorders and in their treatment. In this article, these advances will be reviewed in the same order as a physician should consider them when seeing a new patient with non-Hodgkin's lymphoma: the diagnosis is considered first, followed by the prognosis, choice of treatment, and treatment itself.Clinically Important Subtypes of Non-Hodgkin's LymphomaUnlike the related disorder Hodgkin's disease, non-Hodgkin's lymphoma has a firmly . . .
GASTRIC HETEROTOPIA: A RARE SMALL BOWEL FINDING TREATED ENDOSCOPICALLY WITH DOUBLE-BALLOON ENTEROSCOPY (DBE) (WITH VIDEO)
Authors: N Lazaridis, A Murino, J Watkins, R Raymond, N Koukias, A Skamnelos, T Yano, EJ Despott
Journal: Endoscopy (2020)

Heterotopic gastric mucosa (HGM) is a rare entity that can occur anywhere in the gastrointestinal tract; its exact genesis remains unclear. While HGM is usually asymptomatic, it can occasionally cause bleeding, obstruction and perforation.
Diagnosis and Immunotherapy of Mould Allergy
Authors: H.‐J. Malling
Journal: Allergy (1985)

To determine reproducibility and the optimal way of expressing skin sensitivity, simultaneous skin prick tests (SPT) and intradermal tests (ICT) were performed on 25 mould‐allergic patients. The patients had a well‐documented history of allergy to Cladosporium and Alternaria and were tested with partially purified standardized extracts of these two mould species. Skin prick tests were carried out on the volar side of the forearm and intradermal tests on the backs of the patients. The skin tests were performed as titration using quadruplicate determinations of 10‐fold allergen dilutions. The area of the skin reactions measured by planimetry were plotted in a log‐log system as a function of the allergen concentration. The reproducibility (SD/mean area × 100%) of the ICTs was significantly higher than that of the SPTs (17% versus 29%). A very low reproducibility was found with wheal areas &lt; 5 mm 2 . The dose response curve of the SPT wheal area was steeper than that obtained with ICT, both concerning ICT wheal and flare. Increasing the allergen concentration with a factor 10 resulted in a doubling of the wheal area in SPT, in contrast to a factor 1.7 using ICT. The coefficient of correlation using linear regression on the dose response curve was always higher than 0.9 with SPT and ICT wheal, but significantly lower with ICT flare. Skin sensitivity was estimated as end‐point and histamine equivalent reaction. No significant correlation between SPT and ICT end‐point titration was found contrary to the histamine equivalent reaction. The difference in allergen concentration between end‐point and histamine equivalent reaction was a factor 500 (median) for both SPT and ICT. Due to the lower reproducibility of small skin reactions, the histamine equivalent reaction is to be preferred as an estimate of skin sensitivity. The simplicity and the steeper dose response curve of SPT outweigh the lower reproducibility compared with ICT, and with the use of potent allergen extracts, ICT has no advantages over SPT.
Patterns of Sedentary Behavior and Mortality in U.S. Middle-Aged and Older Adults
Authors: Keith M. Diaz, Virginia J. Howard, Brent Hutto, Natalie Colabianchi, John E. Vena, Monika M. Safford, Steven N. Blair, Steven P. Hooker
Journal: Annals of Internal Medicine (2017)

Although total sedentary time has been associated with increased mortality, most studies have relied on participant recall to report activity. Whether longer or shorter bouts of inactivity are asso...
IS IT WORTH REPEATING CAPSULE ENDOSCOPY (CE) IN SUSPECTED SMALL BOWEL BLEEDING?
Authors: S Sihag, E McCarthy, S Semenov, M Syafiq Ismail, D Molloy, B Ryan, A O’Connor, N Breslin, D McNamara
Journal: Endoscopy (2020)

Aims Repeat CE procedures over 9 years for a suspicion of ongoing SB bleeding were identified from a database. Patient demographics, CE findings and additional investigations were recorded. Potential factors associated with improved yields were explored.
Abstract 15295: Increased Plasma Xanthine Oxidoreductase Activity is Associated With Coronary Artery Spasm
Authors: Ken Watanabe, Tetsuro Shishido, Tetsu Watanabe, Yoichiro Otaki, Takayo Murase, Takashi Nakamura, Takayuki Sugai, Taku Toshima, Tetsuya Takahashi, Miyuki Yokoyama, Daisuke Kinoshita, Harutoshi Tamura, Satoshi Nishiyama, Hiroki Takahashi, Takanori Arimoto, Takuya Miyamoto, Isao Kubota
Journal: Circulation (2017)

Introduction: Increased reactive oxygen species (ROS) contributes to the development of endothelial dysfunction, which is involved in coronary artery spasm (CAS). Xanthine oxidoreductase (XOR) play...
Investigation of a COVID-19 outbreak in Germany resulting from a single travel-associated primary case: a case series
Authors: Merle M Böhmer, Udo Buchholz, Victor M Corman, Martin Hoch, Katharina Katz, Durdica V Marosevic, Stefanie Böhm, Tom Woudenberg, Nikolaus Ackermann, Regina Konrad, Ute Eberle, Bianca Treis, Alexandra Dangel, Katja Bengs, Volker Fingerle, Anja Berger, Stefan Hörmansdorfer, Siegfried Ippisch, Bernd Wicklein, Andreas Grahl, Kirsten Pörtner, Nadine Muller, Nadine Zeitlmann, T Sonia Boender, Wei Cai, Andreas Reich, Maria an der Heiden, Ute Rexroth, Osamah Hamouda, Julia Schneider, Talitha Veith, Barbara Mühlemann, Roman Wölfel, Markus Antwerpen, Mathias Walter, Ulrike Protzer, Bernhard Liebl, Walter Haas, Andreas Sing, Christian Drosten, Andreas Zapf
Journal: The Lancet Infectious Diseases (2020)

In December, 2019, the newly identified severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) emerged in Wuhan, China, causing COVID-19, a respiratory disease presenting with fever, cough, and often pneumonia. WHO has set the strategic objective to interrupt spread of SARS-CoV-2 worldwide. An outbreak in Bavaria, Germany, starting at the end of January, 2020, provided the opportunity to study transmission events, incubation period, and secondary attack rates.