Flu Scan for Nov 14, 2018

News brief

Study finds 9-month drop-off in flu vaccine effectiveness in kids

In children, flu vaccine effectiveness declines over 9 months following immunization, according to a study in Hong Kong that took place over five flu seasons. A team based at the University of Hong Kong reported its findings on Nov 12 in The Lancet Respiratory Medicine.

Flu circulates almost year-round in Hong Kong, and the team used a test-negative case-control design to study vaccine effectiveness in children ages 6 months to 17 years, focusing on changes in the interval between vaccination and hospital admission.

Of 15,695 children hospitalized with respiratory infection from Sep 1, 2012, to Aug 31, 2017, 2,500 (15.9%) tested positive for flu and 13,195 (84.1%) tested negative. Of the vaccinated patients, 159 (6.4%) tested positive for flu and 1,445 (11%) tested negative.

Most of the children were vaccinated in December of each flu season. Pooled vaccine effectiveness declined over the following months, dropping from 79% for September through December, to 67% for January to April, to 43% for May to August. In a separate analysis, the investigators estimated that vaccine effectiveness dropped by 2 to 5 percentage points each month.

The team concluded that the findings support the importance of annual vaccination in children and the need for a flu vaccine that can provide broader, longer-lasting protection.

In a related commentary, two vaccine experts from Australia wrote that the findings have important policy implications and will likely raise questions about modeling studies that health planners use to predict the effect of vaccination strategies. They said uncertainties about the predicted effect of flu vaccines are especially relevant for tropical places like Hong Kong, where flu circulation is more unpredictable.
Nov 12 Lancet Respir Med abstract
Nov 12 Lancet Respir Med commentary

WHO: Global flu at interseasonal levels in much of the world

Most areas of the world reported interseasonal flu levels this past week with some regions reporting increased activity, according to the latest global flu update from the World Health Organization (WHO).

In most of the Northern Hemisphere and the temperate regions of the Southern Hemisphere, flu held at intersessional levels, with influenza A being the most widely circulating type. Several nations in Europe and North America saw a rise in reports of influenza-like illnesses.

Southeast Asia and India reported increased flu activity, as did several nations in northern and western Africa. Respiratory illness indicators started to increase in some west Asian countries, as well.

In the second half of October, the WHO said 86% of specimens positive for the flu were typed as influenza A and 14% as influenza B. Of the sub-typed influenza A viruses, 64.5% were 2009 H1N1 and 35.5% were H3N2. Of the characterized B viruses, 52.4% belonged to the B-Yamagata lineage and 47.6% to the B-Victoria lineage.
Nov 12 WHO update

News Scan for Nov 14, 2018

News brief

Measles clusters grow to 103 cases in New York, New Jersey

The total in three measles clusters—two in New York and one in New Jersey—has grown to 103 cases, according to updates yesterday.

The largest is an outbreak in New York's Rockland County that has now sickened 68 people. The outbreak has been under way since the end of September and was triggered by an international traveler who arrived in the area with a suspected infection. In an update yesterday, Rockland County officials said additional measles cases in infected international travelers have exposed even more people.

Rockland County is located in the New York City suburbs, and the cases are clustered in eastern Ramapo, but, because of the country's small size, officials say exposure could occur anywhere. In response to the outbreak, the county and medical clinics have administered 6,100 doses of measles, mumps, and rubella (MMR) vaccine.

Meanwhile, a measles outbreak centered in the Brooklyn, N.Y., Orthodox Jewish community has grown to 24 confirmed cases, according to NYC Health. The outbreak began in October, with the initial case linked to an unvaccinated child who was exposed to measles on a visit to Israel, where a large outbreak is ongoing.

Elsewhere, a measles cluster in Ocean County, N.J., has now sickened 11 people, according to an update from the New Jersey Department of Health (NJDH). The county announced the first case on Oct 26, involving an individual who contracted measles during international travel.
Nov 13 Rockland County update
Nov 13 NYC Health update
Nov 13 NJDH update

Study examines transfer of bacteria between hospital surfaces, patients

In a study today in Infection Control and Hospital Epidemiology, researchers from Duke University and the University of North Carolina observed the transmission of multidrug-resistant organisms (MDROs) between the hospital environment and patients in nearly 20% of encounters.

In the prospective cohort study, which was conducted at two hospitals, the researchers sought to characterize the nature of bacterial transfer events between patients and environmental surfaces using four "marker" MDROs known for their propensity to contaminate and persist on hospital surfaces: methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant enterococci (VRE), Clostridioides difficile, and multidrug-resistant Acinetobacter baumannii. Although contaminated surfaces are thought to play a role in spreading healthcare-associated infections, the nature, direction, persistence, and quantity of bacterial transfer between surfaces and patients remains poorly understood.

The researchers collected data on 80 patient-room encounters in 68 general ward rooms. Environmental and patient microbiological samples were obtained on admission into a freshly disinfected inpatient room, and repeat samples from room surfaces and patients were taken on days 3 and 7 and each week the patient stayed in the same room. The two primary outcomes of interest were the baseline and subsequent patterns of patient colonization and hospital surface contamination, and the number of microbiologic and molecularly proven bacterial transfer events between hospital surfaces and patients.

In total, 9 patients (11.3%) were asymptomatically colonized with MDROs at study entry. Hospital rooms were contaminated with MDROs despite terminal disinfection in 44 of 80 patient rooms (55%) at the time of study enrollment. The researchers detected microbiologic bacterial transfer events in 12 of 65 patients (18.5%), with 4 occurring from the patient to the environment, 4 occurring from the environment to the patient, and 4 of indeterminate direction. In 2 of the encounters, the patient acquired the MDRO present in the environment at the time of admission.

The study authors conclude, "This study suggests that research on prevention methods beyond the standard practice of room disinfection at the end of a patient's stay is needed to better prevent acquisition of MDROs through the environment."
Nov 14 Infect Control Hosp Epidemiol abstract