You will be shown an abstract from a biomedical research paper. Given this abstract, your task is to extract all unique entities of the following types: ["Outcome", "Participant", "Intervention"].

Please return the output as a JSON object of the format: {"Participant" : ["patients with COPD", ...], "Intervention" : ["Atenolol", ...], "Outcome" : ["blood pressure", ...]}. The keys should be entity types and values should be lists of extracted entities belonging to the corresponding type. If you cannot find entities belonging to a specific type, the value should be [].

Only output the JSON object and do not include any additional text.

Abstract:

Randomised placebo-controlled trial of rhesus-human reassortant rotavirus vaccine for prevention of severe rotavirus gastroenteritis . BACKGROUND Rotavirus is the most common cause of acute childhood gastroenteritis . Vaccination with live oral heterologous rotavirus vaccines may prevent rotavirus gastroenteritis . We assessed the efficacy of rhesus-human reassortant rotavirus tetravalent vaccine ( RRV-TV ) against severe rotavirus gastroenteritis in Finnish children in a randomised placebo-controlled double-blind trial . METHODS Placebo or RRV-TV ( titre 4x10 ( 5 ) plaque-forming units ) was given to infants at ages 2 , 3 , and 5 months . The children were followed up for one or two rotavirus epidemic seasons . The main outcome measure was protection against severe rotavirus gastroenteritis ( score > or =11 on a 20-point severity scale ) . 2398 children were enrolled and received at least one dose of RRV-TV ( n=1191 ) or placebo ( n=1207 ) . The primary efficacy analysis was based on children who received three doses of RRV-TV ( n=1128 ) or placebo ( n=1145 ) . FINDINGS 256 episodes of rotavirus gastroenteritis occurred at any time during the study ; 65 were among 1191 RRV-TV recipients , and 191 among 1207 placebo recipients ( vaccine efficacy 66 % [ 95 % CI 55-74 ] ; intention-to-treat analysis ) . 226 episodes were included in the primary efficacy analysis of fully vaccinated children ( 54 among 1128 RRV-TV recipients , 172 among 1145 placebo recipients ; vaccine efficacy 68 % [ 57-76 ] ) . 100 episodes were severe , eight in RRV-TV recipients and 92 in placebo recipients ( vaccine efficacy 91 % [ 82-96 ] ) . INTERPRETATION RRV-TV vaccine was highly effective against severe rotavirus gastroenteritis in young children . Incorporation of this vaccine into routine immunisation schedules of infants could reduce severe rotavirus gastroenteritis by 90 % and severe gastroenteritis of all causes in young children by 60 % .
{"Intervention": ["RRV-TV", "placebo", "rhesus-human reassortant rotavirus vaccine", "Placebo", "placebo-controlled", "rhesus-human reassortant rotavirus tetravalent vaccine ( RRV-TV )", "RRV-TV vaccine"], "Outcome": ["severe gastroenteritis", "efficacy", "severe rotavirus gastroenteritis"], "Participant": ["young children", "2398", "children", "infants at ages 2 , 3 , and 5 months"]}