News Scan for Feb 18, 2019

More MERS infections
US flaccid myelitis cases
H9N2 avian flu case in China
Flu A and B illness differences
Human H3N2 flu challenge

More MERS cases reported in Saudi Arabia, all linked to camels

According to updates posted this weekend and through today, Saudi Arabia has three more MERS-CoV cases, including two in Wadi ad-Dawasir.

On Feb 16 the Ministry of Health (MOH) recorded two new cases of MERS-CoV (Middle East respiratory syndrome coronavirus) for epidemiologic week 7, including in a 65-year-old man from Wadi ad-Dawasir who had camel contact. That patient is currently hospitalized. The MOH also said a 78-year-old man from the Tabuk region also contracted the virus after camel contact. That patient died.

Today the MOH recorded a case in a 53-year-old man from Wadi ad-Dawasir, the first in epidemiologic week 8. The patient also had camel contact and is hospitalized for his infection.

The Saudi MOH has now confirmed 65 MERS infections since Jan 1, with 41 of those cases recorded in Wadi ad-Dawasir.
Feb 16 MOH
Feb 18 MOH


CDC confirms 6 new acute flaccid myelitis cases

The US Centers for Disease Control and Prevention (CDC) reported 5 new cases of the polio-like condition known as acute flaccid myelitis (AFM) for last year and 1 new case for 2019, according to an update today.

The newly reported 2018 cases raise last year's numbers to 215 cases. The 215 cases are among 371 reports of PUIs (patients under investigation) and constitute the highest annual total the CDC has ever recorded. 

"So far in 2019, there have been 11 reports of PUIs, one of which has been confirmed (from North Carolina,)" the CDC said in its biweekly update on the mysterious disease dated Feb 15. "CDC and state and local health departments are still investigating some of the PUIs. CDC is not aware of any deaths in confirmed AFM cases with illness onsets in 2018 or 2019."

Texas has reported the most AFM cases, with 29. Colorado has 16 cases, Ohio has 14, and Washington state and California have 11. Minnesota, Pennsylvania, and New Jersey have each recorded 10.

AFM activity tends to spike in an every-other-year pattern. The CDC first started tracking the disease in August of 2014, and that portion of the year saw 120 cases. In 2015 the agency confirmed 22 cases, in 2016 there were 149, and 2017 saw 35 cases.

AFM affects the spinal cord, leaving patients—almost always children—with partial or total limb paralysis or muscle weakness. The cause of the disease is unknown, but 90% of patients report upper respiratory virus symptoms in the weeks prior to limb weakness. In previous years the syndrome has been tied to enterovirus infections.
Feb 15 CDC


H9N2 avian flu infects one more person in China

China has reported another H9N2 avian flu illness, which involves an 8-year-old from Yunnan province, according to a Macao Health Bureau statement translated and posted by Avian Flu Diary (AFD), an infectious disease news blog.

The girl's symptoms began on Jan 27, and she reportedly has a mild infection, which fits the typical pattern for H9N2. The strain is endemic in Chinese poultry, and exposure to poultry is a known risk factor in sporadic human illnesses.

China reported seven cases in 2018, including one noted in early February in a boy from Hunan province whose symptoms began in late December.
Feb 16 AFD post


Study finds influenza A patients sicker for longer compared with flu B

A study to gauge the difference in illness severity between influenza A and influenza B in hospitalized patients found that people infected by influenza A were sicker and recovered more slowly, researcher from China reported late last week in Open Forum Infectious Diseases.

The observational study included adult patients admitted to China-Japan Friendship Hospital in Beijing with lab-confirmed seasonal flu from Oct 1, 2016, to Jun 1, 2018. In line with treatment guidance, patients were usually treated with neuraminidase inhibitors if they sought care or were hospitalized within 48 hours of illness onset. The team collected clinical data and rated clinical outcome on a seven-category scale that ranged from discharge with normal activity to death.

Of 574 patients included in the study, 369 (64.3%) had influenza A and 205 (35.7%) had influenza B. On admission, patients with influenza A had worse clinical symptoms. By day 28, 82.4% of patients with influenza A had improved, compared with 90.7% of patients with influenza B. Also, patients with influenza B had a higher clinical improvement probability compared with those with influenza A (adjusted hazard ratio, 1.266; 95% confidence interval, 1.019 to 1.573; P = 0.0335). The researchers saw similar patterns for weaning supplemental oxygen, and they found that hospital mortality for influenza A was slightly higher than for influenza B—11.4% versus 6.8%.

When the researchers adjusted for confounding factors such as time of initial antiviral treatment, age, and underlying diseases, they found the same results.

They said the findings need to be validated by multicenter studies and added that their study wasn't designed to detect differences among the two influenza A strains or the two influenza B lineages.
Feb 15 Open Forum Infect Dis abstract


H3N2 human challenge yields key data for developing vaccines

A human challenge study using seasonal H3N2 flu virus, the first of its kind to be grown in mammalian cells and produced with reverse genetics, found that it can be administered safely to produce mild-to-moderate disease, a key step in developing and evaluating better and more broadly protective flu vaccines.

A team based at the National Institutes of Allergy and Infectious Diseases (NIAID) clinical studies unit reported its findings in Clinical Infectious Diseases.

Of 49 healthy adults younger than 50 who were enrolled in the study from December 2015 through July 2017, 37 were included in the analysis. Patients were inoculated intranasally in a stepwise fashion. The researchers monitored viral shedding, symptoms, and immune responses. Of those challenged, 16 (43%) had viral shedding and 27 (73%) developed symptoms, 12 (32%) of them with mild-to-moderate severity.

Only the patients receiving the highest intranasal doses had mild-to-moderate disease. Clinical symptoms were typical for flu, including headache, fatigue, nasal and sinus congestion, rhinorrhea, and sore throat. Symptoms peaked on day 3, with most shedding occurring 1 to 2 days after challenge. Only 10 patients (29%) had a fourfold or greater rise in hemagglutinin inhibition antibody titer after challenge.

Compared with an earlier 2009 H1N1 challenge study, the H3N2 trial caused fewer mild-to-moderate symptoms and less shedding, though the incidence of symptoms was similar. The investigators said the fewer anti hemagglutinin antibody responses that they observed, taken together with less mild-to-moderate disease, suggests that other preexisting immunity factors may limit shedding in healthy volunteers.

The team wrote that a percentage of people with low hemagglutinin inhibition antibody titers who are unprotected may not develop antibody response to current or future HA-based vaccines and could be a factor in vaccine failure, a  phenomenon seen both H1N1 and H3N2 infections. "In addition, these individuals may have other pre-challenge protective immune correlates that were not assessed," they added. The authors noted that antibodies against neuraminidase were less variable, a finding seen now in both H1N1 and H3N2 human infection models.

"Significant questions remain that should be addressed in future challenge studies with this virus and other influenza viruses regarding what aspects of immunity are the most protective, including antibodies against the NA, T-cell immunity, mucosal immunity, and other factors that are potentially playing a very important role in protection," they wrote.
Feb 16 Clin Infect Dis abstract

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