News Scan for Nov 26, 2013

News brief

WHO confirms 3 Saudi MERS cases, 2 deaths

The World Health Organization (WHO) today confirmed three cases of Middle East respiratory syndrome coronavirus (MERS-CoV) infection in Saudi Arabia that the country's Ministry of Health (MOH) first reported last week. Two of the cases proved fatal.

As has been the pattern with Saudi MERS-CoV cases, the WHO report contained little information on the cases.

Two patients, both of whom died on Nov 18, are from Riyadh. One was a 73-year-old woman with underlying medical conditions who became ill Nov 12 and was hospitalized Nov 14. The second is a 37-year-old man who developed symptoms Nov 9 and was hospitalized Nov 13. The Saudi MOH reported the first case Nov 19 and the second on Nov 21.

The third WHO-confirmed MERS case-patient is a 65-year-old man from Al Jawf region who has an underlying medical condition. He became ill on Nov 4 and was hospitalized on Nov 14, but the agency did not specify his current condition. On Nov 19 the Saudi MOH said he had been taken to an intensive care unit.

The WHO said none of the patients were exposed to animals or had contact with any confirmed cases.

Since September 2012 the WHO has reported 160 lab-confirmed MERS-CoV cases, including 68 deaths. Of those, 130 cases and 55 deaths have been from Saudi Arabia.
Nov 26 WHO statement
Nov 19 CIDRAP News story "Saudi Arabia reports 2 more MERS cases"
Nov 21 CIDRAP News scan on 37-year-old patient

Primate study hints at source of pertussis vaccine problem

As a clue that might help science unravel the reasons behind a steep rise in pertussis cases, researchers who conducted primate experiments found that the acellular vaccine wasn't able to prevent infection or prevent transmission. The study, conducted by researchers from the US Food and Drug Administration (FDA), appeared yesterday in Proceedings of the National Academies of Sciences (PNAS).

The scientists vaccinated baby baboons at ages 2, 4, and 6 months with either the acellular or whole-cell vaccine, then infected them with Bordetella pertussis at 7 months. Investigators monitored the animals' symptoms and took nasopharyngeal washes to assess colonization. To test transmission, they placed the animals in cages with unvaccinated ones.

Baboons immunized with the acellular vaccine were protected from severe symptoms but not colonization, and they didn't clear the infection any faster than naive animals. Also, they easily transmitted the pathogen to unvaccinated cage mates. The researchers also found that previously infected animals were not colonized when exposed to infection again.

Animals vaccinated with the whole-cell vaccine cleared the infection faster than the naive and acellular groups. Though all groups had robust immune responses, researchers found a key difference in the T-cell profile: The previous-infection and whole-cell groups showed a similar pattern.

The suboptimal response to the acellular vaccine may help explain some of the disease resurgence and suggests the need to develop better pertussis vaccines, the team concluded. They noted that the findings suggest the cocoon strategy many not help protect babies from pertussis, but that the vaccine seems to reduce serious disease and that efforts to boost vaccination should continue.
Nov 25 PNAS abstract

In another pertussis development, the Indian Academy of Pediatrics recently revised its pertussis vaccine recommendations, proposing whole-cell vaccination for the infant series.

The group based its recommendation on evidence of waning protection in acellular vaccines. It also recommended the tetanus, diphtheria, and pertussis (Tdap) vaccine for pregnant women to protect young infants. The position paper appears in Indian Pediatrics.
November Indian Pediatrics abstract

More polio cases in Syria, kidnapped Pakistani health workers released

Two new cases of polio caused by wild poliovirus type 1 (WPV-1) have been reported from Syria, bringing the total in the current outbreak there to 17, says a news report today from the WHO.

The first 15 case-patients were from Deir Al Zour province in the eastern part of the country; the two new ones are from rural Damascus in the southwest and Aleppo in the northwest, signaling widespread circulation of WPV-1. The risk of spread is considered high because of frequent population movements due to the political situation there, the report says.

Mass polio vaccination campaigns targeting 22 million children under age 5 are part of a regional outbreak response including seven countries and territories. Containment efforts are likely to continue for 6 to 8 months or more, and the WHO and the UN Children's Fund (UNICEF) are committed to vaccinating all children "no matter where they live," says the report.
Nov 26 WHO release

In other polio developments, Pakistani polio workers who were kidnapped from a school in the northwestern part of that country several days ago have been released, according to a BBC News report today. Apparently the militants responsible for the kidnapping, thought to be part of the Lashkar-e-Islam group, agreed to the release after the government said no more vaccination teams would be sent into the Bara area of the country's Khyber tribal region, says the story.

The number of people in the kidnapped group, said to include teachers, is not clear, but they are expected to reach Peshawar tomorrow. Pakistan is one of only three countries where polio remains endemic. Militants reportedly think vaccination workers are spies or are attempting to sterilize Muslims, according to the story.
Nov 26 BBC News item
Nov 25 CIDRAP News scan on the kidnapping

Flu Scan for Nov 26, 2013

News brief

Study finds vaccine protects about half of pregnant women from flu

Flu vaccine effectiveness (VE) varied from 44% to 53% over the 2010-11 and 2011-12 seasons among pregnant women, and getting a flu shot the previous year appeared to be just as effective as getting the current year's vaccine, according to a study in Clinical Infectious Diseases today.

Researchers from the Centers for Disease Control and Prevention's (CDC's) Pregnancy and Influenza Project Workgroup conducted a case-control study among Kaiser Permanente patients in two metropolitan areas in California and Oregon. They compared the vaccination rate in 100 lab-confirmed influenza case-patients with that of 192 controls who had acute respiratory illness (ARI) who tested negative for flu and 200 controls who did not have ARI and tested negative.

The team found an adjusted VE for the current-season vaccine against influenza A and B of 44% (95% confidence interval [CI], 5%-67%) using the influenza-negative controls for comparison and 53% (95% CI, 24%-72%) using the ARI-negative controls.

They also noted: "Receipt of the prior season's vaccine, however, had an effect similar to receipt of the current season's vaccine. As such, vaccination in either or both seasons had statistically similar adjusted VE using influenza-negative controls (VE point estimates range = 51%-76%) and ARI-negative controls (48%-76%)."
Nov 26 Clin Infect Dis abstract

H3N2 gene study finds flu mutations more predictable than thought

A study of seasonal H3N2 viruses that circulated from 1968 to 2003 found that mutations were more predictable than previously thought. An international team from the Netherlands, the United Kingdom, Australia, Russia, and the United States reported their findings in the Nov 22 issue of Science.

The team looked at genetic sequences of representative H3N2 viruses from 11 antigenic clusters that emerged during the 35-year period, a time that followed the introduction of the strain in humans. Their goal was to pinpoint the substitutions that drove the antigenic changes.

They found that at least 9 of 10 cluster transitions were mainly caused by single amino acid substitutions, and all of the substitutions occurred as seven positions close to the receptor binding site on the hemagglutinin. Five of the seven key positions occurred twice.

When they infected ferrets with viruses that contained the single amino acid changes they found differences in virus-specific antibody response. The researchers also found that similar positions drove recent antigenic changes in seasonal H1N1 and influenza B viruses.

The findings suggest that nature has selected for substitutions at only 7 of 131 positions that can cause antigenic changes, the team wrote. "This is an important change in our understanding of the antigenic evolution of seasonal influenza viruses."

The team also noted that the location of the key positions near the receptor-binding sites provides a clue that antibodies specific to that area play a key role in neutralizing the H3N2 virus.

Researchers noted that it's surprising that antigenic clusters appear relatively slowly, roughly every 3.3 years, given the high mutation rate of flu viruses and the observation that single amino acid substitutions can lead to new antigenic clusters. They suggested that the antigenic changes could come with a fitness cost that slows virus evolution.
Nov 22 Science abstract

CDC contest seeks flu season predictions from use of social media

The CDC has launched a competition aimed at modeling and predicting influenza activity, according to a news release from the agency yesterday.

Called "Predict the Influenza Season Challenge," the contest will award $75,000 to the entrant who is able to most successfully predict the timing, peak, and intensity of the current flu season nationally and at each or any Health and Human Services region level through mathematical and statistical models that use digital (social media) surveillance data, say details of the contest published in the Federal Register.

The competition is part of a national system of contests used by more than 50 government agencies that seeks to spur innovative solutions to national problems at a fraction of the cost of traditional means of funding.
Nov 25 CDC news release
Nov 25 Federal Register item giving details of the contest