News Scan for May 09, 2018

More romaine E coli cases
Predicting pandemic severity
Lassa fever cases
HPV vaccine meta-analysis

E coli outbreak tied to romaine lettuce grows to 149 cases, 29 states

The Centers for Disease Control and Prevention (CDC) today confirmed 28 new cases of Escherichia coli infections and four newly affected states in an outbreak tied to eating romaine lettuce from the Yuma, Ariz., growing region that has caused higher rates of severe disease than is typically seen with E coli.

The outbreak has now reached 149 cases in 29 states, including 1 death. Of 129 patients with available information, 64 (50%) have been hospitalized, 17 with hemolytic uremic syndrome (HUS), a potentially deadly kidney complication. The date of first symptoms ranges from Mar 13 to Apr 25. Officials have noted that the harvest in the Yuma growing season is now over, but the lettuce might remain in people's homes.

"Illnesses that occurred in the last two to three weeks might not yet be reported because of the time between when a person becomes ill with E. coli and when the illness is reported to CDC," the CDC said in its update.

Patients range in age from 1 to 88 years, with a median age of 30.

The newly affected states are Minnesota (10 cases), North Dakota (2), Florida (1), and Texas (1). The Minnesota Department of Health (MDH) detailed its confirmed cases in a news release yesterday. It noted that 9 patients were female, 3 required hospitalization, 2 had HUS, and all reported exposure to romaine lettuce. "Reported exposure locations include restaurants, grocery stores, and residential facilities," the MDH said.

The CDC has yet to name a specific producer but instead warns, "Do not eat or buy romaine lettuce unless you can confirm it is not from the Yuma growing region."
May 9 CDC update
May 8 MDH news release



New model based on 2009 H1N1 flu predicts pandemic severity

Using clinical data from the 2009 H1N1 epidemic, flu experts created a new model that predicts the clinical severity of an emerging pandemic virus. The research was published yesterday in Clinical Infectious Diseases.

An international group of authors said experts initially overestimated clinical severity during the H1N1 pandemic, predicting in the early months of the outbreak that case-fatality rates (CFRs) would rival the 1918 pandemic. H1N1 proved to be much milder, prompting the World Health Organization to declare severity a requirement for pandemic status.

Ongoing clinical trials for other diseases are the basis for establishing such a severity model. Using data collected from 2009 to 2011 under the International Network for Strategic Initiatives in Global HIV Trials (INSIGHT) umbrella, the researchers developed a model that accurately calculated the probability of progression from outpatient to hospitalization, and from hospitalization to death, based on patients enrolled in the trials from 2009 to 2011. The model produced CFRs that were comparable to established data.

"Going forward, clinical research networks with a global presence and standardized protocols would substantially aid rapid assessment of clinical severity," the authors concluded.
May 8 Clin Infect Dis study  


Three new cases of Lassa fever in Nigeria

The Nigeria Centre for Disease Control (NCDC) confirmed three new cases of Lassa fever and no deaths for the week ending on May 6. Since Jan 1, the NCDC has recorded 423 confirmed cases of the virus, including 106 deaths.

Officials detected the three new cases in Edo (2) and Ebonyi (1) states. Edo is the most-affected state, with 42% of confirmed cases. Sixteen percent of confirmed cases have been recorded in Ebonyi. None of the new cases involved healthcare workers.

The CFR in confirmed cases is 25.1%. The NCDC said seven cases are currently being monitored in four treatment centers across the country.  

Lassa fever is endemic in Nigeria, but this has been the country's largest outbreak. The virus is spread by rodents, but human-to-human transmission can occur via infected bodily fluids.
May 6 NCDC report


Cochrane review: HPV vaccine prevents cervical precancer

The human papillomavirus (HPV) vaccine protects young women from developing cervical cancer, according to the latest meta-analysis conducted by the Cochrane Library.

More than 70% of all cervical cancers develop after infections with HPV types 16 or 18, strains contained in both the bivalent and quadrivalent vaccines.

The authors of the review looked at 26 studies involving 73,428 women across all continents in the past 8 years to see if the bivalent and quadrivalent HPV vaccine protected women from cervical cancer. Though none of the studies surveyed have been conducted long enough to answer the question definitely, there is clear evidence the vaccine protects women against developing precancer cervical lesions, the investigators reported.

According to the review, for girls and women aged 15 to 26 years, the vaccine reduced the risk of cervical precancer associated with HPV 16 or 18 from 341 to 157 per 10,000 women and reduced the risk for any precancer lesions from 559 to 391 per 10,000. The vaccines effects diminished among older women aged 25 to 45, who most likely were exposed to HPV before receiving the vaccine.

"There is high-certainty evidence that HPV vaccines protect against cervical precancer in adolescent girls and young women aged 15 to 26," the review concluded. "The effect is higher for lesions associated with HPV16/18 than for lesions irrespective of HPV type. The effect is greater in those who are negative for hrHPV [high-risk HPV] or HPV16/18 DNA at enrolment than those unselected for HPV DNA status."
May 9 Cochrane Library study

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