Mark Katz

Dr. Mark Katz

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Research Focus & Metrics

Academic Career Length

20Years (2007-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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23 June 2014 in PLOS ONE
Verified
Journal Article
Open access
PDF file
MKMark Katz
Mark Katz
PMPhilip Muthoka
Philip Muthoka
GEGideon O. Emukule
Gideon O. Emukule
RKRosalia Kalani
Rosalia Kalani
HNHenry Njuguna
Henry Njuguna
JMJoshua A. Mott
Joshua A. Mott
Recent studies have shown that influenza is associated with significant disease burden in many countries in the tropics, but until recently national surveillance for influenza was not conducted in most countries in Africa. In 2007, the Kenyan Ministry of Health with technical support from the CDC-Kenya established a national sentinel surveillance system for influenza. At 11 hospitals, for every hospitalized patient with severe acute respiratory illness (SARI), and for the first three outpatients with influenza-like illness (ILI) per day, we collected both nasopharyngeal and oropharyngeal swabs. Beginning in 2008, we conducted in-hospital follow-up for SARI patients to determine outcome. Specimens were tested by real time RT-PCR for influenza A and B. Influenza A-positive specimens were subtyped for H1, H3, H5, and (beginning in May 2009) A(H1N1)pdm09. From July 1, 2007 through June 30, 2013, we collected specimens from 24,762 SARI and 14,013 ILI patients. For SARI and ILI case-patients, the median ages were 12 months and 16 months, respectively, and 44% and 47% were female. In all, 2,378 (9.6%) SARI cases and 2,041 (14.6%) ILI cases were positive for influenza viruses. Most influenza-associated SARI cases (58.6%) were in children <2 years old. Of all influenza-positive specimens, 78% were influenza A, 21% were influenza B, and 1% were influenza A/B coinfections. Influenza circulated in every month. In four of the six years influenza activity peaked during July–November. Of 9,419 SARI patients, 2.7% died; the median length of hospitalization was 4 days. During six years of surveillance in Kenya, influenza was associated with nearly 10 percent of hospitalized SARI cases and one-sixth of outpatient ILI cases. Most influenza-associated SARI and ILI cases were in children <2 years old; interventions to reduce the burden of influenza, such as vaccine, could consider young children as a priority group.

5 October 2021 in Influenza and Other Respiratory Viruses
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Journal Article
Open access
PDF file
IBIsabel Bergeri
Isabel Bergeri
HLHannah C Lewis
Hannah C Lewis
LSLorenzo Subissi
Lorenzo Subissi
ANAnthony Nardone
Anthony Nardone
MVMarta Valenciano
Marta Valenciano
MKMaria Van Kerkhove
Maria Van Kerkhove
Background: The declaration of Coronavirus disease 2019 (COVID‐19) as a Public Health Emergency of International Concern (PHEIC) on 30 January 2020 required rapid implementation of early investigations to inform appropriate national and global public health actions.Methods: The suite of existing pandemic preparedness generic epidemiological early investigation protocols was rapidly adapted for COVID‐19, branded the ‘UNITY studies’ and promoted globally for the implementation of standardized and quality studies. Ten protocols were developed investigating household (HH) transmission, the first few cases (FFX), population seroprevalence (SEROPREV), health facilities transmission (n = 2), vaccine effectiveness (n = 2), pregnancy outcomes and transmission, school transmission, and surface contamination. Implementation was supported by WHO and its partners globally, with emphasis to support building surveillance and research capacities in low‐ and middle‐income countries (LMIC).Results: WHO generic protocols were rapidly developed and published on the WHO website, 5/10 protocols within the first 3 months of the response. As of 30 June 2021, 172 investigations were implemented by 97 countries, of which 62 (64%) were LMIC. The majority of countries implemented population seroprevalence (71 countries) and first few cases/household transmission (37 countries) studies.Conclusion: The widespread adoption of UNITY protocols across all WHO regions indicates that they addressed subnational and national needs to support local public health decision‐making to prevent and control the pandemic.

25 February 2015 in BMC Infectious Diseases
Verified
Journal Article
Open access
PDF file
RBRobert F Breiman
Robert F Breiman
LCLeonard Cosmas
Leonard Cosmas
MNM Kariuki Njenga
M Kariuki Njenga
JWJohn Williamson
John Williamson
JMJoshua Mott
Joshua Mott
DFDaniel R Feikin
Daniel R Feikin
Reducing acute respiratory infection burden in children in Africa remains a major priority and challenge. We analyzed data from population-based infectious disease surveillance for severe acute respiratory illness (SARI) among children <5 years of age in Kibera, a densely populated urban slum in Nairobi, Kenya. Surveillance was conducted among a monthly mean of 5,874 (range = 5,778-6,411) children <5 years old in two contiguous villages in Kibera. Participants had free access to the study clinic and their health events and utilization were noted during biweekly home visits. Patients meeting criteria for SARI (WHO-defined severe or very severe pneumonia, or oxygen saturation 20% additional cases. Influenza viruses and RSV (and possibly PIV, hMPV and adenoviruses) are important pathogens to consider when developing technologies and formulating strategies to treat and prevent SARI in children.

30 May 2017 in BMC Pregnancy and Childbirth
Verified
Journal Article
Open access
PDF file
MKMark Katz
Mark Katz
BGBradford D. Gessner
Bradford D. Gessner
JJJeanene Johnson
Jeanene Johnson
BSBecky Skidmore
Becky Skidmore
MKMarian Knight
Marian Knight
DFDeshayne B. Fell
Deshayne B. Fell
The World Health Organization (WHO) considers pregnant women to be a risk group for severe influenza disease. We conducted a systematic review to evaluate influenza disease incidence in pregnant women in order to inform estimates of influenza vaccine impact for low-resource countries. We performed electronic literature searches, targeting studies on the following outcomes in pregnant women: attack rate, hospitalization rate, intensive care unit admission rate, mortality rate, and disability-adjusted life years lost. Only original studies published in peer-reviewed journals that had laboratory confirmation for influenza virus infection and included population-based incidence rates with denominator data were included. We summarized study characteristics in descriptive tables and outcome-specific Forest plots. We generated summary incidence rates using random effects models and assessed statistical heterogeneity by visual examination of Forest plots, and by χ 2 and I2 tests. We identified 1543 articles, of which nine articles met the study inclusion criteria. Five were case series, three were cohort studies, and one was a randomized controlled trial. Eight studies were from high-income countries, and one was from an upper middle-income country. Six studies reported results for pandemic influenza, and three reported seasonal influenza. Statistical heterogeneity was high for all outcomes, and methodologies and duration of surveillance varied considerably among studies; therefore, we did not perform meta-analyses. Study quality was very low according to GRADE criteria. More data on influenza disease incidence in pregnant women, particularly in low- and middle-income countries and for seasonal influenza disease, are needed to inform public health decision-making.

24 December 2014 in BMC Medical Informatics and Decision Making
Verified
Journal Article
Open access
PDF file
HNHenry N Njuguna
Henry N Njuguna
DCDeborah L Caselton
Deborah L Caselton
GAGeoffrey O Arunga
Geoffrey O Arunga
GEGideon O Emukule
Gideon O Emukule
DKDennis K Kinyanjui
Dennis K Kinyanjui
JMJoshua Mott
Joshua Mott
For disease surveillance, manual data collection using paper-based questionnaires can be time consuming and prone to errors. We introduced smartphone data collection to replace paper-based data collection for an influenza sentinel surveillance system in four hospitals in Kenya. We compared the quality, cost and timeliness of data collection between the smartphone data collection system and the paper-based system. Since 2006, the Kenya Ministry of Health (MoH) with technical support from the Kenya Medical Research Institute/Centers for Disease Control and Prevention (KEMRI/CDC) conducted hospital-based sentinel surveillance for influenza in Kenya. In May 2011, the MOH replaced paper-based collection with an electronic data collection system using Field Adapted Survey Toolkit (FAST) on HTC Touch Pro2 smartphones at four sentinel sites. We compared 880 paper-based questionnaires dated Jan 2010-Jun 2011 and 880 smartphone questionnaires dated May 2011-Jun 2012 from the four surveillance sites. For each site, we compared the quality, cost and timeliness of each data collection system. Incomplete records were more likely seen in data collected using pen-and-paper compared to data collected using smartphones (adjusted incidence rate ratio (aIRR) 7, 95% CI: 4.4-10.3). Errors and inconsistent answers were also more likely to be seen in data collected using pen-and-paper compared to data collected using smartphones (aIRR: 25, 95% CI: 12.5-51.8). Smartphone data was uploaded into the database in a median time of 7 days while paper-based data took a median of 21 days to be entered (p < 0.01). It cost USD 1,501 (9.4%) more to establish the smartphone data collection system ($17,500) than the pen-and-paper system (USD $15,999). During two years, however, the smartphone data collection system was $3,801 (7%) less expensive to operate ($50,200) when compared to pen-and-paper system ($54,001). Compared to paper-based data collection, an electronic data collection system produced fewer incomplete data, fewer errors and inconsistent responses and delivered data faster. Although start-up costs were higher, the overall costs of establishing and running the electronic data collection system were lower compared to paper-based data collection system. Electronic data collection using smartphones has potential to improve timeliness, data integrity and reduce costs.

1 October 2007 in Emerging Infectious Diseases
Verified
Journal Article
Open access
RBRobert F. Breiman
Robert F. Breiman
ANAbdulsalami Nasidi
Abdulsalami Nasidi
MKMark Katz
Mark Katz
MNM. Kariuki Njenga
M. Kariuki Njenga
JVJohn Vertefeuille
John Vertefeuille
Global concerns about an impending influenza pandemic escalated when highly pathogenic influenza A subtype H5N1 appeared in Nigeria in January 2006. The potential devastation from emergence of a pandemic strain in Africa has led to a sudden shift of public health focus to pandemic preparedness. Preparedness and control activities must work within the already strained capacity of health infrastructure in Africa to respond to immense existing public health problems. Massive attention and resources directed toward influenza could distort priorities and damage critical public health programs. Responses to concerns about pandemic influenza should strengthen human and veterinary surveillance and laboratory capacity to help address a variety of health threats. Experiences in Asia should provide bases for reassessing strategies for Africa and elsewhere. Fowl depopulation strategies will need to be adapted for Africa. Additionally, the role of avian vaccines should be comprehensively evaluated and clearly defined.