EV-D68 associated with another death, as US cases climb
Federal health officials reported today that enterovirus D68 (EV-D68) has been detected in another patient who died recently, as the case count rose to 664 and Tennessee joined the list of affected states.
Today's update from the Centers for Disease Control and Prevention (CDC) put the number of deaths of EV-D68-infected patients at five, one more than before, but it provided no details about the case.
The CDC has said the role of the virus in the deaths is unclear, but New Jersey officials said this week that EV-D68 caused the death of a 4-year-old boy. The CDC said state and local officials have authority to determine the cause of death in such cases and to decide what information to release about them.
The CDC's new tally of 664 confirmed EV-D68 cases is up 36 from yesterday's 628. There have been confirmed cases in 45 states, with Tennessee as the newest one. Only Alaska, Hawaii, Oregon, Nevada, and Arizona still have no confirmed infections, according to the CDC's list.
Almost all the cases have been in children, many of whom have asthma or a history of wheezing, the CDC says. The virus, which was previously uncommon in the United States, typically causes only cold-like symptoms, but some children get seriously ill and have difficulty breathing.
EV-D68 is also suspected of contributing to a mysterious polio-like illness that has struck a number of children in several states, including at least 10 in Colorado. Four of the Colorado children, who had partial paralysis and limb weakness, tested positive for the virus.
CDC EV-D68 outbreak information
CDC list and map of affected states
Studies: Good immune response with adjuvanted avian flu vaccines
Two studies published today in JAMA report good immune response to an adjuvanted H7N9 avian flu vaccine and the promise of priming in an H5N1 avian flu vaccine. Both trials included vaccines with the MF59 adjuvant, an immune-boosting additive.
The first study involved 700 US adults 19 to 64 years old who received injected H7N9 vaccine at doses of 3.75, 7.5, 15, or 45 micrograms (mcg) of hemagglutinin with or without the adjuvant. H7N9 was first detected in people in 2013 and has caused about 450 known cases, almost all of them in China.
The phase 2 trial was conducted at four sites in September 2013, with 6-month follow-up completed in May 2014. Participants received two doses 21 days apart.
The highest dose induced minimal antibody responses against H7N9, the researchers reported. Two 3.75-mcg doses of adjuvanted vaccine, however, were associated with a day-42 seroconversion rate (a minimum fourfold increase to titer 40 or greater) of 59%. Higher doses, adjuvanted or not, were not associated with increased immune response.
The authors write, "The significant antigen dose-sparing effect of MF59 is an important finding, potentially allowing for protection of many more people with limited vaccine," but they add that the study is limited by the absence of antibody data beyond 42 days and the absence of clinical outcomes.
Oct 8 JAMA abstract on H7N9 vaccine
The second study found that immunologic priming—early introduction of an antigen to help boost later vaccine response—may prove helpful with H5N1 vaccine.
The study involved 72 volunteers who had received one or two doses of an H5N1 vaccine using a 2004 Vietnam strain and then received an H5N1 vaccine that contained a 2005 strain from China. It also involved 565 vaccine-naive participants who received doses of the vaccine with the China strain ranging from 3.75 to 90 mcg.
The researchers found that a single dose of Vietnam vaccine was associated with an increased immune response to the China vaccine. The secondary antibody responses were brisk, with responses seen by day 7 and peaking 14 days after the boosting vaccination.
As with the H7N9 vaccine trial, the authors of this study also noted the dose-sparing potential of the MF59 adjuvant with the H5N1 vaccine.
Oct 8 JAMA abstract on H5N1 vaccines
Oct 8 JAMA editorial on both studies
Oct 8 JAMA news release on the studies
Trial shows promise of adjuvanted split-virion H5N1 vaccine
In yet another study on avian flu vaccines, a phase 2/3 trial of a split-virion H5N1 with a different adjuvant showed a good immune response and safety profile in children, according to a study in the Journal of Infectious Diseases.
An international team of scientists vaccinated children aged 6 months to 17 years with a vaccine containing an H5N1 strain obtained from an Indonesian patient in 2005. Participants received two doses 21 days apart, each containing 1.9 mcg of antigen and an AS03B adjuvant.
Immunogenicity was assessed 21 days after the second dose for all volunteers, plus at day 182 for half and day 385 for the rest.
"Within each age stratum, lower limit of the 98.3% confidence interval (CI) for the Day 42 seroprotection rate was >70% thus fulfilling the United States and European licensure criteria," the authors reported. They added, "The immune responses elicited by vaccine persisted well above baseline for 1 year."
They reported no major safety concerns versus placebo.
Oct 6 J Infect Dis abstract
Bomb kills 2 off-duty polio workers in Pakistan
An improvised explosive device (IED) blast in Pakistan yesterday killed two brothers who were part of a polio vaccination team that is working to reach children in the northwestern part of the country, according to news sources.
Whether the men, who were off duty, were specifically targeted remains unclear, although vaccination teams have been continually attacked by Taliban fighters over the past couple of years, with more than 60 health workers and security personnel killed to date. No group has claimed responsibility for the current bombing so far.
Militants in the war-torn northern provinces of Pakistan maintain that vaccination campaigns are acts of Western espionage and that the vaccine is being used to sterilize Muslims, notes a story from the Al Jazeera media network.
One factor behind this misinformed view is that during the hunt for Osama Bin Laden, a Pakistani physician was recruited by the US Central Intelligence Agency to pose as a vaccinator to gain entrance to residences.
The IED explosion occurred in Mohmand agency, a district in the Federally Administered Tribal Areas (FATA) near the border with Afghanistan. The victims were walking near the home of one; an article from Agence France-Presse (AFP) says their cousin, who was not a health worker, was also killed, and a search for suspects is under way.
Pakistan has had more than 200 cases of polio this year, the most of any country and a 14-year record for the country.
Oct 8 Al Jazeera story
Oct 8 AFP story
