l. NIH announced today that its PREVAIL trial of two experimental vaccines in Liberia opened today to volunteers. The study will enroll 27,000 volunteers. NIH describes the two experimental vaccines as follows:
“One vaccine candidate, cAd3-EBOZ, uses a chimpanzee-derived cold virus to deliver Ebola virus genetic material from the Zaire strain of virus causing the outbreak in Liberia. Published interim results from a Phase 1 trial of this vaccine, which was co-developed by NIAID scientists and GlaxoSmithKline, provided necessary safety information and showed that it prompted immune responses to the outer coat of Ebola virus. The other candidate, VSV-ZEBOV, employs vesicular stomatitis virus, an animal virus that primarily affects cattle, to carry an Ebola virus gene segment. The VSV-ZEBOV vaccine was developed by the Public Health Agency of Canada and licensed to NewLink Genetics Corporation through its wholly owned subsidiary BioProtection Systems Corporation. Phase 1 trial results of this vaccine also provided safety information and showed that it prompted immune responses to the outer coat of Ebola virus. These results have not yet been published but were made available to the regulatory bodies reviewing the study.”
See the entire NIH announcement at: http://www.nih.gov/news/health/feb2015/niaid-02.htm. The announcement contains a Q & A re: how the clinical trials will be performed.
2. NY Times reports that Chimerix has stopped the trial of its experimental drug brincinofovir in Liberia due to lack of enrollment. The company says the number of EBOV cases has decreased to a small number and their trial cannot enroll the 140 patients required. Brincinofovir was primarily developed for treatment of other viral diseases; some activity against EBOV was found in vitro. Chimerix will devote its trials toward approval of this drug for other viruses. See: http://www.nytimes.com/2015/02/02/business/ebola-drug-trial-is-halted-for-lack-of-patients.html?ref=health&_r=0 for the NY Times article.
3. PLoS Currents Outbreaks has posted on-line today an article by Cuesta, et. al. of Norway and Denmark and DRC and Netherlands re: the effectiveness of the recent MSF mass vaccination program in DRC against measles virus. The mass vaccination program did not reach sufficient children to prevent recurrence of measles. The causes of non-vaccination were primarily: family absence, lack of knowledge of date/time for vaccinations, and distance to vaccination sites:
“Children who had not been vaccinated for any of the campaigns reported that absence of the family in the village on the vaccination day was the main reason for non-vaccination, when they were asked about MVC (33%) and EPI (71%) (Figure 1). The second most reported reason among these not vaccinated children was lack of knowledge about time or place of vaccination during the MVC (5%) and EPI (28%). The vaccination site being too far away was also mentioned by these children for the MVC (5%) and EPI (10%) (Figure 1).”
These same causes may also impede the success of the EBOV vaccine trials begun today, unless trial coordinators take note of the Cuesta, et. al. article and take countermeasures. See this article at: http://currents.plos.org/outbreaks/article/measles-vaccination-coverage-survey-in-moba-katanga-democratic-republic-of-congo-2013-need-to-adapt-routine-and-mass-vaccination-campaigns-to-reach-the-unreached/