Two-year follow-up study on cholera vaccine shows good efficacy
A 2-year follow-up study of the single-dose oral cholera vaccine (OCV) showed it was effective in adults and children over the age of 5 years. Consistent with results from the 6-month follow-up, the vaccine failed to protect children under the age of 5 from the disease.
The study was published yesterday in The Lancet Infectious Diseases and is based on a 2014 Bangladeshi trial that randomly assigned participants to either a placebo or the vaccine. The overall incidence rates of initial cholera episodes during the 2 years were 0.22 (95% confidence interval [CI], 0.18 to 0.27) per 100,000 person-days in vaccine recipients versus 0.36 (95% CI, 0.31 to 0.42) per 100,000 person-days in placebo recipients (adjusted protective efficacy 39%; 95% CI, 23% to 52%).
For recipients ages 5 to 15, the vaccine was 52% effective in protecting against all cholera and 71% effective in protecting against severe episodes. For adults, the vaccine protective efficacy was 59% against all cholera episodes.
"The lower protective efficacy in young children might be explained by their lower prevaccination exposure to and immunological priming by natural cholera infections, as well as the nature of the protective antigen in the OCV, which might require immunological priming," the authors said.
The authors warn that the lack of efficacy should not deter countries from using the vaccine for older children and adults during an outbreak, and said further investigation into OCV and young immune systems is needed.
Mar 14 Lancet Infect Dis study
Mar 14 Lancet Infect Dis commentary
H5N6 strikes Dutch poultry farm, wild bird in Sweden
The Netherlands has reported its second highly pathogenic H5N6 avian flu outbreak in poultry, and Sweden has detected the virus again in a wild bird, according to separate report from the World Organization for Animal Health (OIE).
The Dutch outbreak began on Mar 12 at a commercial poultry farm in Overijssel province in the east central part of the country, killing 100 of 28,886 birds. The rest were culled to curb the spread of the virus. Health officials have also established surveillance and protection zones around the facility, and so far all farms within 3 kilometers of the affected location have tested negative for the virus, which is a reassortant related to the H5N8 virus.
The Netherlands' first H5N6 outbreak in poultry occurred in February in Groningen province, north of where the newly reported outbreak.
In Sweden, H5N6 was detected in a buzzard found dead on Feb 24 in Blekinge County in the south. The event marks the country's second detection of H5N6 in a wild bird.
In other avian flu outbreak developments, Taiwan reported seven more highly pathogenic H5N2 outbreaks at commercial poultry farms. The events began from Feb 22 to Mar 5, affecting meat ducks, layer ducks, and native chickens. Six of the farms are in Yunlin County, and one is in Pingtung County. Taken together, the virus killed 810 of 54,403 susceptible birds, and the rest were destroyed as part of the outbreak response.
Mar 15 OIE report on H5N6 in the Netherlands
Mar 14 OIE report on H5N6 in Sweden
Mar 15 OIE report on H5N2 in Taiwan
Health officials take steps to address Africa's rise in monkeypox cases
An increase in monkeypox cases across Africa and lack of strong surveillance in the affected areas has raised the level of global concern over the zoonotic disease, experts from the World Health Organization (WHO) and the US Centers for Disease Control and Prevention (CDC) reported today in the latest issue of Morbidity and Mortality Weekly Report (MMWR).
They wrote that the WHO and CDC hosted an informal consultation on monkeypox in November 2017 that brought together researchers, global health partners, health ministers, and orthopoxvirus experts to review recent human cases and discuss surveillance and response areas that need improvement.
Six African countries have confirmed human cases since 2016, many of which had not reported a case in decades. They are Central African Republic, Democratic Republic of the Congo, Liberia, Nigeria, Republic of Congo, and Sierra Leone. The virus has also been detected in captive chimpanzees in Cameroon. Most recently, an outbreak in Nigeria resulted in 80 confirmed cases, the largest outbreak of its kind to occur in West Africa. "The emergence of cases is a concern for global health security," the group wrote.
Though overall surveillance has improved in West Africa, health providers in many countries lack the knowledge to recognize and treat the infections or how to curb the spread of monkeypox. Also, the group wrote that outbreaks often occur in forested areas that have limited access to health services.
To address some of the gaps, the WHO and CDC are prioritizing several work areas, such as developing updated guidance and regional training and improving capacity for lab surveillance, disease detection, patient care, and outbreak response.
Mar 16 MMWR report