News Scan for May 31, 2016

News brief

Newer antibiotics more costly but not necessarily better than old

At a time when growing bacterial resistance underlines the need for new antibiotics, records on eight antibiotics approved in the United States from 2010 to 2015 suggest that they cost more than older drugs but don't necessarily offer clear clinical advantages, according to a study published today in Annals of Internal Medicine.

The researchers examined the development process, pivotal trials, cost data, and other information on the eight drugs: ceftaroline, fidaxomicin, bedaquiline, dalbavancin, tedizolid, oritavancin, ceftolozane-tazobactam, and ceftazidime-avibactam. Data sources included Food and Drug Administration (FDA) documents, industry reference books, company filings, press releases, and media reports.

Four of the antibiotics "were approved for acute bacterial skin and skin-structure infections," the report says. "Seven had similar mechanisms of action to those of previously approved drugs. Six were initially developed by small to midsized companies, and 7 are currently marketed by 1 of 3 large companies."

Clinical trials of the drugs took a median of 6.2 years, and the FDA spent a median of 8 months reviewing them.

Seven of the eight drugs were approved on the basis of trials designed to determine whether they were non-inferior to existing antibiotics with similar indications, the authors found. One drug was found to be superior to existing drugs for one "exploratory secondary end point," but one was linked to increased mortality compared with older drugs, and two showed decreased efficacy in patients with renal insufficiency.

On the basis of prices listed in public sources, "Seven of the drugs are substantially more expensive than their trial comparators," the authors wrote. They conclude, "Recently marketed antibiotics are more expensive but have been approved without evidence of clinical superiority."

But they caution that future research may reveal benefits not yet apparent and that new drugs from older classes may work better in specific groups of patients.
May 31 Ann Intern Med abstract

PAHO reports 1,100 new chikungunya infections

The Pan American Health Organization (PAHO) late last week reported 1,184 new chikungunya cases, bringing the 2016 total to 115,383 cases.

During the previous week the agency reported a jump of 27,505 suspected and confirmed cases, but the weeks before that saw increases of only 996 and 3,095 cases. PAHO updated its numbers on May 27.

Ecuador had the most new cases, with 486, bringing its total for the year to 1,053. Colombia was not far behind, with 481 new cases and 14,801 total. Many countries, though, have not reported new cases for many weeks.

No new deaths were reported, keeping that number at 15, all in Brazil.

The outbreak was first reported in December 2013 on St. Martin in the Caribbean with the first recorded cases of the disease in the Americas. Since then PAHO has reported 1,995,350 suspected or confirmed cases, including 283 fatalities.
May 27 PAHO update

In related news, Kenya's North Eastern Region is being hit by both chikungunya and cholera, straining local medical services, Medecins Sans Frontieres (MSF, or Doctors without Borders) reported on May 27. The outbreak is centered on Mandera Township, population 90,000.

Health officials in the region reported 260 suspected chikungunya cases, 7 of which have been confirmed. And the area has had almost 800 cholera cases since April, including 11 fatalities.
May 27 MSF report

Measles cases rise to 11 at immigrant detention center in Arizona

A measles outbreak at a federal detention center for immigrants in central Arizona has grown to 11 cases, the Associated Press (AP) reported yesterday.

The outbreak began last week when an infected detainee was brought to the center and spread the disease to a vaccinated worker. Officials have confirmed that seven inmates and four workers now have measles at the Eloy Detention Center, Pinal County Health Services spokesman Joe Pyritz said.

Health officials have isolated patients, vaccinated detainees, and pieced together locations that the four infected workers visited. They have identified 14 locations in Pinal and Maricopa counties of potential exposure to the highly contagious disease, including stores, restaurants, and a casino.
May 30 AP story

Study: Males have higher pneumococcal disease rates than females

An analysis of 25 years' worth of illness data collected in Tennessee found that the rate of invasive pneumococcal disease (IPD) was higher in males than females, especially in young children and middle-aged adults, according to a study yesterday in the Journal of Infectious Diseases.

The researchers used Tennessee IPD data for 1988 through 2013 from the Centers for Disease Control and Prevention's Active Bacterial Core Surveillance program. They identified 8,383 cases, with disease most common among those 40 to 64 years old (39% of cases) and over 75 (17%). Males accounted for 53% of all cases.

IPD rates were significantly higher in males than females in most age-groups, the authors found. This held true regardless of race and both before and after the introduction of seven-valent pneumococcal conjugate vaccine (PCV7) in 2010 and of PCV13 in 2010—events that led to substantial declines in rates.

The gender differences were clearest among children under 2 years old and adults ages 40 through 64 years. For example, the incident rate ratio (IRR) for males versus females in those under 2 in the pre-vaccine era was 1.6 (95% confidence interval, 2.1 to 2.0). In the post-PCV13 era the IRR for this group increased to 2.0 (95% CI, 1.1 to 3.4)

For 40- to 64-year-olds, the male-to-female IRR was 1.6 (95% CI, 1.2 to 2.0) in the pre-vaccine era but dropped to 1.3 (95% CI, 1.1 to 1.6) after PCV13's arrival. Differences were smaller in those 2 to 17, 18 to 39, and over 65 years old.

The authors say the reasons for the gender differences are unclear, particularly since males and females had similar levels of comorbidities, such as chronic lung disease and a history of smoking. Their findings point up the need for more research on possible behavioral and biological explanations of the differences, they conclude.
May 30 J Infect Dis abstract

WHO reports 273 Lassa fever cases in Nigeria, 149 deaths

Nigeria has had 273 cases of Lassa fever since August 2015, an increase of more than 100 cases since late January, the World Health Organization (WHO) reported on May 27.

Of the 273 cases, 149 (55%) have been fatal; 165 cases have been lab-confirmed, or 54% of the total, including 89 deaths. Twenty-three states have reported cases.

The total includes 10 health workers, 4 of whom contracted the disease in a healthcare setting. Two of the 10 died.

As of May 17, eight states are still reporting cases or are following up on contacts of cases for the 21-day incubation period. The other 15 states have completed the 42-day period following the last known transmission.

On Jan 27, in its previous update for Nigeria, the WHO reported 159 cases, including 82 deaths.
May 27 WHO statement
Jan 27 WHO statement

Flu Scan for May 31, 2016

News brief

China reports human H5N6 case in Hunan province

Chinese officials last week reported a human case of H5N6 avian flu, according to a post today on FluTrackers, an infectious disease message board.

The case involves a 50-year-old man from Jishou city in Hunan province's Xiangxi autonomous prefecture, FluTrackers said. He is hospitalized in critical condition.

The new case is the second H5N6 infection to have occurred in Hunan province, and it lifts the global case total to 15 since the virus emerged in April 2014. Nine H5N6 cases have been reported in China this year, FluTrackers said.
May 30 FluTrackers post
FluTrackers H5N6 case list

Cameroon reports H5N1 outbreak in poultry

Cameroon reported a recent H5N1 avian flu outbreak on a poultry farm, according to a May 27 report to the World Organization for Animal Health (OIE).

Cameroon's H5N1 outbreak began May 20 on a large farm in the capital city of Yaounde, located in the country's Centre region. Of the 33,000 breeders, boilers, and layers on the farm, 15,000 died from the infection, and the remaining 18,000 were culled to prevent the spread of the virus, the OIE said.

The outbreak was detected when officials observed high mortality among breeding birds during routine surveillance. Control measures, including disinfection and quarantine, have been implemented, the OIE said.
May 27 OIE report

Study shows chickens readily transmit H7N9 to quail

Meanwhile, a recent study in Virology found that chickens transmit H7N9 avian flu poorly to other chickens but can infect nearby quail.

Researchers from Colorado State University and the US Department of Agriculture National Wildlife Research Center were able to characterize aspects of H7N9 avian flu transmission by simulating a live-animal market containing chickens, common quail, pigeons, and rabbits, according to findings published last week in Virology.

Four domestic chickens inoculated with the H7N9 virus were unable to produce an infection and viral shedding in two chickens caged with them. All four quail housed in cages directly below the infected chickens, however, seroconverted and began shedding virus between 3 and 11 days following exposure. Oral shedding in the quail was more than 10 times greater than titers observed in directly infected chickens, the authors said.

Pigeons and cottontail rabbits housed near the infected chickens showed no sign of infection. Environmental testing on 120 fecal and 100 water samples produced negative results for live virus, the authors said.

Given the findings, live-animal markets should not place cages of chickens and quail in proximity, the authors said.
May 26 Virology study

Review: Wide range of bacterial co-infections found in flu patients

The prevalence of bacterial co-infections in patients hospitalized with influenza ranges from 2% to 65%, a variation that highlights the importance of conserving antibiotic treatment for only those bacterial cases diagnosed by a positive test, according to a May 27 study in Influenza and Other Respiratory Diseases.

Researchers conducted a meta-analysis of 27 studies published since 1982 and comprising 3,215 patients hospitalized with lab-confirmed flu. The prevalence of bacterial co-infection was from 2% in a population of US newborns to 65% in French adults, the authors said. When seven studies accounting for more than half of the variation were excluded, the range of co-infection prevalence among 2,058 patients narrowed to 11% to 35%.

Rates of bacterial co-infection were similar for children and adults and rose only slightly for patients in the intensive care unit. Four studies that examined comorbidities found that co-infection was associated with flu severity, older age, diabetes, and sepsis, the authors said.

Among the eight studies that identified causes of co-infection, cases were most commonly due to Streptococcus pneumoniae (35% of cases) and Staphylococcus aureus (28%); other identified species included Pseudomonas aeruginosa, Streptococcus pyogenes, Haemophilus influenzae, and Klebsiella pneumonia, among others. Findings of significant species variation support the use of broad-spectrum antibiotics for flu-related pneumonia, the authors said, adding that routine testing for methicillin-resistant S aureus is advisable, especially for cases of community-acquired pneumonia.

Six studies found that providers may have underestimated the frequency of bacterial co-infection because of prior antibiotic use in 12% to 50% of flu patients, and one study found that previous antibiotic use made flu patients more likely to acquire an atypical bacterial infection, the authors said.

The authors cautioned providers to refrain from assuming that hospitalized flu patients require antibiotics and instead treat underlying viral illness and to confirm bacterial infection with routine cultures before initiating treatment. Additionally, more studies are needed to better characterize the frequency and diversity of bacterial infections in non-hospitalized flu patients, the authors said.
May 27 Influenza Other Respir Viruses study