( CNN ) The first doses of the Ebola vaccine were on a commercial flight to West Africa and were expected to arrive on Friday , according to a spokesperson from GlaxoSmithKline ( GSK ) one of the companies that has created the vaccine with the National Institutes of Health . Another vaccine from Merck and NewLink will also be tested . `` Shipping the vaccine today is a major achievement and shows that we remain on track with the accelerated development of our candidate Ebola vaccine , '' Dr. Moncef Slaoui , chairman of global vaccines at GSK said in a company release . Ebola who is patient zero ? In December , the trial of the vaccine made by Merck and NewLink were stopped after some of the volunteers in the trial had `` transient mild '' joint pain . After investigating that side effect , scientists concluded it was not a big enough issue to stop the development of the vaccine . No similar side effects were noted in the GSK trial . There are other Ebola vaccines being tested by companies in the United States and in Russia . This first shipment will be used , along with a placebo in this first large-scale trial in the next few weeks in Liberia . `` We are expecting to start by the last week in January , but there are some details that need to be ironed out regarding the FDA , '' said Dr. Anthony Fauci , the director of the National Institute of Allergy and Infectious Diseases ( NIAID ) at a press conference . Worst Ebola outbreak in history : What you should know . The tests should begin in the Monrovia area and will involve nearly 30,000 people . People who have had the virus and survived will be excluded from this trial , according to GSK . The first people to get the vaccine will be health care workers who are some of the population that is most at risk for catching Ebola . That 's because it can be easily transmitted through exposure to bodily fluids . In Liberia there have been 370 cases of health care workers becoming infected with Ebola , 178 of them have died according to the World Health Organization . The number of newly infected health care workers has declined recently , as has the number of cases in general in Liberia . Hope for Ebola epidemic 's end in Liberia . In August and September of 2014 the WHO was seeing 300 new confirmed cases per week , versus the 8 new confirmed cases according to this latest incident report . Another trial in Sierra Leone should start a few weeks after the trials get started in Liberia , according to the NIH . Sierra Leone has had the largest number of infections of any country with 10,340 reported cases and 3,145 deaths from Ebola . The disease has slowed down according to the WHO , but still there were 117 new confirmed cases according to the latest report . The Centers for Disease Control and Prevention will work with Sierra Leone 's government to help manage the tests . The NIH will also soon be testing the therapeutic drug ZMapp as early as next month . Ebola Fast Facts . ZMapp is an experimental drug that has been used to help patients who have already been infected by the virus . The drug maker , Mapp Biopharmaceutical ran out of the drug last year , but has been making enough doses for a small human trial . The number of new Ebola cases in Liberia has been declining , but public health leaders say that there are still `` little mini outbreaks '' and that `` until there is a very last case , ( an epidemic ) is not over until it is over , '' Fauci said . Since the outbreak began in December 2013 , there have been 21,759 infections and 8,668 people have died from Ebola .
The first vials of an Ebola vaccine should land in Liberia Friday . Some 37,000 people are expected to be involved in the first large-scale test of the vaccine . Health care workers will be the first to get the vaccine as they are most vulnerable .