Asymptomatic Orthopoxvirus Circulation in Humans in the Wake of a Monkeypox Outbreak among Chimpanzees in Cameroon.

is a zoonotic (OPXV) that causes smallpox-like illness in humans. In Cameroon, human monkeypox cases were confirmed in 2018, and outbreaks in captive chimpanzees occurred in 2014 and 2016. We investigated the OPXV serological status among staff at a primate sanctuary (where the 2016 chimpanzee outbreak occurred) and residents from nearby villages, and describe contact with possible monkeypox reservoirs.

Update: Influenza Activity - United States and Worldwide, May 19-September 28, 2019, and Composition of the 2020 Southern Hemisphere Influenza Vaccine.

During May 19-September 28, 2019,* low levels of influenza activity were reported in the United States, with cocirculation of influenza A and influenza B viruses. In the Southern Hemisphere seasonal influenza viruses circulated widely, with influenza A(H3) predominating in many regions; however, influenza A(H1N1)pdm09 and influenza B viruses were predominant in some countries. In late September, the World Health Organization (WHO) recommended components for the 2020 Southern Hemisphere influenza vaccine and included an update to the A(H3N2) and B/Victoria-lineage components.

Investigation of an Outbreak of Variant Influenza A(H3N2) Virus Infection Associated With an Agricultural Fair-Ohio, August 2012.

Background: In 2012, one third of cases in a multistate outbreak of variant influenza A(H3N2) virus ([H3N2]v) infection occurred in Ohio. We conducted an investigation of (H3N2)v cases associated with agricultural Fair A in Ohio.

Methods: We surveyed Fair A swine exhibitors and their household members.

Influenza activity - United States, 2013-14 season and composition of the 2014-15 influenza vaccines.

During the 2013-14 influenza season in the United States, influenza activity increased through November and December before peaking in late December. Influenza A (H1N1)pdm09 (pH1N1) viruses predominated overall, but influenza B viruses and, to a lesser extent, influenza A (H3N2) viruses also were reported in the United States. This influenza season was the first since the 2009 pH1N1 pandemic in which pH1N1 viruses predominated and was characterized overall by lower levels of outpatient illness and mortality than influenza A (H3N2)-predominant seasons, but higher rates of hospitalization among adults aged 50-64 years compared with recent years.

Update: influenza activity - United States, September 29, 2013-February 8, 2014.

Influenza activity in the United States began to increase in mid-November and remained elevated through February 8, 2014. During that time, influenza A (H1N1)pdm09 (pH1N1) viruses predominated overall, while few B and A (H3N2) viruses were detected. This report summarizes U.

Outbreak of variant influenza A(H3N2) virus in the United States.

Background: Variant influenza virus infections are rare but may have pandemic potential if person-to-person transmission is efficient. We describe the epidemiology of a multistate outbreak of an influenza A(H3N2) variant virus (H3N2v) first identified in 2011.

Methods: We identified laboratory-confirmed cases of H3N2v and used a standard case report form to characterize illness and exposures.

Human infections with influenza A(H3N2) variant virus in the United States, 2011-2012.

BACKGROUND. During August 2011-April 2012, 13 human infections with influenza A(H3N2) variant (H3N2v) virus were identified in the United States; 8 occurred in the prior 2 years. This virus differs from previous variant influenza viruses in that it contains the matrix (M) gene from the Influenza A(H1N1)pdm09 pandemic influenza virus.

Estimates of the number of human infections with influenza A(H3N2) variant virus, United States, August 2011-April 2012.

Background: Thirteen human infections with an influenza A(H3N2) variant (H3N2v) virus containing a combination of gene segments not previously associated with human illness were identified in the United States from August 2011 to April 2012. Because laboratory confirmation of influenza virus infection is only performed for a minority of ill persons and routine clinical tests may not identify H3N2v virus, the count of laboratory-confirmed H3N2v virus infections underestimates the true burden of illness.

Methods: To account for this underascertainment, we adapted a multiplier model created at the beginning of the influenza A(H1N1) 2009 pandemic to estimate the true burden of H3N2v illness.

Using routine surveillance data to estimate the epidemic potential of emerging zoonoses: application to the emergence of US swine origin influenza A H3N2v virus.

Background: Prior to emergence in human populations, zoonoses such as SARS cause occasional infections in human populations exposed to reservoir species. The risk of widespread epidemics in humans can be assessed by monitoring the reproduction number R (average number of persons infected by a human case). However, until now, estimating R required detailed outbreak investigations of human clusters, for which resources and expertise are not always available.

Outbreak of influenza A (H3N2) variant virus infection among attendees of an agricultural fair, Pennsylvania, USA, 2011.

During August 2011, influenza A (H3N2) variant [A(H3N2)v] virus infection developed in a child who attended an agricultural fair in Pennsylvania, USA; the virus resulted from reassortment of a swine influenza virus with influenza A(H1N1)pdm09. We interviewed fair attendees and conducted a retrospective cohort study among members of an agricultural club who attended the fair. Probable and confirmed cases of A(H3N2)v virus infection were defined by serology and genomic sequencing results, respectively.

Expanding the recommendations for annual influenza vaccination to school-age children in the United States.

Background: Despite long-standing recommendations to vaccinate children who have underlying chronic medical conditions or who are contacts of high-risk persons, vaccination coverage among school-age children remains low. Community studies have indicated that school-age children have the highest incidence of influenza and are an important source of amplifying and sustaining community transmission that affects all age groups.

Methods: A consultation to discuss the advantages and disadvantages of a universal recommendation for annual influenza vaccination of all children age ≥6 months was held in Atlanta, Georgia, in September 2007.

Influenza viruses in Thailand: 7 years of sentinel surveillance data, 2004-2010.

Background: The re-emergence of avian influenza A (H5N1) in 2004 and the pandemic of influenza A (H1N1) in 2009 highlight the need for routine surveillance systems to monitor influenza viruses, particularly in Southeast Asia where H5N1 is endemic in poultry. In 2004, the Thai National Institute of Health, in collaboration with the U.S.

Surveillance for influenza during the 2009 influenza A (H1N1) pandemic-United States, April 2009-March 2010.

The emergence in April 2009 and subsequent spread of the 2009 pandemic influenza A (H1N1) virus resulted in the first pandemic of the 21st century. This historic event was associated with unusual patterns of influenza activity in terms of the timing and persons affected in the United States throughout the summer and fall months of 2009 and the winter of 2010. The US Influenza Surveillance System identified 2 distinct waves of pandemic influenza H1N1 activity--the first peaking in June 2009, followed by a second peak in October 2009.

Effects of adverse events on the projected population benefits and cost-effectiveness of using live attenuated influenza vaccine in children aged 6 months to 4 years.

Objective: To evaluate the effect of adverse events associated with live attenuated influenza vaccine (LAIV) in children younger than 5 years on the cost-effectiveness of influenza vaccination.

Design: A decision analytic model was developed to predict costs and health effects of no vaccination, vaccination with LAIV, and vaccination with inactivated influenza vaccine (IIV). Probabilities, costs, and quality adjustments for uncomplicated influenza, outpatient visits, hospitalizations, deaths, vaccination, and vaccine adverse events were based on primary and published data.

Episodic illness, chronic disease, and health care use among homeless persons in Metropolitan Atlanta, Georgia, 2007.

Background: Homeless persons are at higher risk for morbidity and mortality from both chronic and episodic illness than the general population. Few data are available on the prevalence of these conditions and uptake of vaccination for prevention.

Methods: In March 2007, we administered a cross-sectional survey to a convenience sample of homeless persons in Atlanta.

Infections with oseltamivir-resistant influenza A(H1N1) virus in the United States.

Context: During the 2007-2008 influenza season, oseltamivir resistance among influenza A(H1N1) viruses increased significantly for the first time worldwide. Early surveillance data suggest that the prevalence of oseltamivir resistance among A(H1N1) viruses will most likely be higher during the 2008-2009 season.

Objectives: To describe patients infected with oseltamivir-resistant influenza A(H1N1) virus and to determine whether there were any differences between these patients and patients infected with oseltamivir-susceptible A(H1N1) virus in demographic or epidemiological characteristics, clinical symptoms, severity of illness, or clinical outcomes.