WHO releasing yellow fever vaccine to battle deadly outbreak in Ethiopia
To combat a deadly yellow fever outbreak in Ethiopia, the World Health Organization (WHO) announced it will release 1.45 million doses of the yellow fever vaccine from its emergency stockpile, Reuters reported today.
The outbreak began in August in the Wolaita zone of the Southern Nations, Nationalities, and Peoples' Region. So far, 35 cases have been confirmed, and 10 people have died from the mosquito-borne disease.
"This outbreak is of concern since the population of Ethiopia is highly susceptible to yellow fever due to absence of recent exposure and lack of large-scale immunizations," the WHO said in a Nov 2 report.
Following an immediate reactive vaccination campaign conducted in mid-October, around 31,000 people have been vaccinated against yellow fever, and the country said it plans to introduce the yellow fever vaccine into a routine immunization schedule in 2020.
Ethiopia previously experienced frequent yellow fever outbreaks until the 1960s, but there were no outbreaks of the virus until 2013, when the disease re-emerged in the same region with 143 cases.
Nov 6 Reuters story
Nov 2 WHO Africa regional report
Phase 2 trial shows chikungunya vaccine to be safe, immunogenic
Results from a phase 2 trial of a live-attenuated, measles-vectored chikungunya vaccine (MV-CHIK) showed the vaccine to be safe, well-tolerated, and immunogenic, according to a study published yesterday in The Lancet that did not assess efficacy.
Healthy adults ages 18 to 55 in Austria and Germany were enrolled in the study and randomly assigned to receive MV-CHIK, measles vaccine used as a control, or priming with the measles vaccine, then MV-CHIK, in two different administration regimens. Researchers defined immunogenicity as the presence of neutralizing antibodies against chikungunya at day 56. A total of 263 volunteers participated in the study.
According to the trial results, all participants in the MV-CHIK treatment groups produced neutralizing antibodies after one or two immunizations, with geometric mean titers ranging from 12.87 (95% confidence interval [CI], 8.75–18.93) to 174.80 (95% CI, 119.10–256.50) and seroconversion rates ranging from 50.0% to 95.9%, depending on the dose and administration schedule.
Though injection-site tenderness was widely reported among MV-CHIK recipients, no serious adverse events were recorded.
"We found that the MV-CHIK vaccine had a safety and tolerability profile that was similar to the measles control vaccine," the authors concluded. "On the basis of these data, we are preparing a phase 3 study of MV-CHIK," which will assess vaccine protection against chikungunya infection.
In a commentary on the study in the same issue, arboviral disease expert Ann M. Powers, PhD, of the US Centers for the Disease Control and Prevention, said, "The approach has some distinct advantages over other platforms, including the use of a measles virus vector that has a long established use and safety record. Additionally, because the measles vector is viable, it should generate multiple rounds of chikungunya virus-like particles, which should enhance immunogenicity."
She added, however, "Curiously, the antibody titres generated in response to either a single or even a boost dose of the vaccine were at least an order of magnitude lower than those seen with other virus-like particle vaccine candidates. . . . The lower neutralising antibody titre with MV-CHIK might be an issue once an antibody threshold necessary for immunity has been established. One other limitation of MV-CHIK is the clear need for more than one dose of vaccine."
Nov 5 Lancet study
Nov 5 Lancet commentary
Russia, Bulgaria report more high-path H5 avian flu outbreaks
Russia and Bulgaria reported new highly pathogenic avian flu outbreaks in poultry, according to notifications today from the World Organization for Animal Health (OIE), as the WHO European regional office warned authorities and residents of countries located on wild bird migration routes to be vigilant about avian flu outbreaks.
Russia's outbreak started Oct 31 at a commercial farm in Voronezh oblast in the far western part of the country. Testing detected an H5 strain, and the event killed 122,300 of 342,300 susceptible birds. The remaining ones were slated for culling as part of outbreak control measures.
The country has reported a steady stream of H5 outbreaks since June, and it reported its last one on Oct 1.
Meanwhile, Bulgaria, which has been battling a spate of H5N8 outbreaks, reported three more detections, one at a commercial farm in Plovdiv province and two in Haskovo province, two involving farms and the other backyard birds. The outbreaks began between Oct 29 and Oct 31, and, taken together, the virus killed 4,338 of 43,327 poultry. The surviving ones were destroyed to curb the spread of the virus.
Nov 6 OIE report on H5 in Russia
Nov 6 OIE report on H5N8 in Bulgaria
In a statement today, the WHO's regional office for Europe pointed out that in autumn wild birds migrate southwest to overwinter in warmer climates. The agency noted that, since June, Russia has reported 80 highly pathogenic H5 outbreaks, one of them involving H5N2, along major bird migration routes. "Given the presence of avian influenza viruses in the Region, their spread to other countries is likely," the statement said.
Russian officials said the most recent outbreak was caused by an H5N8 virus that is closely related to the strain that caused widespread outbreaks in Europe during the winter of 2016-17, resulting in millions of birds being culled and large economic losses. The WHO said so far no human infections from H5N8 or H5N2 have been reported, but the virus warrants close monitoring for any changes.
Nov 6 WHO European regional office statement