Gastroenteritis%20-%20viral Management

• Prevention of most cases of viral gastroenteritis depends on the use of safe and effective vaccines
  • Universal immunization against rotavirus is recommended by the WHO
• Currently, 4 vaccines are available to prevent severe diarrhea caused by rotavirus infection
  • Several studies support that early vaccination simulate initial natural infection, thus preventing subsequent severe cases of rotavirus gastroenteritis
• Vaccines against norovirus are currently being developed with preliminary results showing good tolerability in children

Human Rotavirus Vaccine

• Contains live attenuated human rotavirus strain
• Prevents gastroenteritis caused by the most common genotypes G1P[8], G2P[4], G3P[8], G4P[8] and G9P[8]
  • Effectiveness has also been demonstrated against the less common genotypes G9P[4] and G9P[6] and the uncommon genotypes G8P[4] (severe gastroenteritis) and G12P[6] (any gastroenteritis) 
• Based on a clinical study done in Asia, the vaccine showed a 100% protective efficacy against severe gastroenteritis during the 1st year of life with the efficacy sustained up to 3 years of age
• Can be simultaneously administered with the following vaccines without affecting the immune responses and safety profiles of the administered vaccines:
  • Hepatitis B vaccine (HBV)
  • Inactivated polio vaccine (IPV)
  • Haemophilus influenzae type b vaccine (Hib)
  • Pneumococcal conjugate vaccine (PCV)
  • Meningococcal serogroup C conjugate vaccine 
  • Diphtheria-tetanus-acellular pertussis vaccine (DTPa/DTaP)
  • Diphtheria-tetanus-whole cell pertussis vaccine (DTPw/DTwP)
  • Hexavalent vaccines (DTPa-HBV-IPV/Hib)
• Concomitant administration with oral polio vaccine (OPV) may slightly reduce the immune response to rotavirus vaccine; however, the clinical protection of rotavirus vaccine against severe gastroenteritis would not be affected
  • It is advised that 2 weeks should lapse between administration of the 2 vaccines

Pentavalent Rotavirus Vaccine

• Contains live reassortant rotaviruses developed from human and bovine hosts
• Prevents gastroenteritis caused by serotypes G1P1A[8], G2P1[4], G3P1A[8], G4P1A[8] and G9P1A[8]
  • Efficacy in preventing any grade of gastroenteritis severity reached 72.5-74% based on 2 studies done from the time of completion of 3-dose regimen through the 1st rotavirus season after the vaccination
  • The 2 trials also showed that the vaccine has clinical efficacy of 98-100% in preventing severe cases
  • There is a 95.8% reduction in hospitalizations for severe gastroenteritis during the 1st 2 years following the final dose
• May be simultaneously administered with the following vaccines without affecting the immune responses of the administered vaccines: HBV, IPV, OPV, Hib, PCV, DTPa, meningococcal serogroup C conjugate vaccine and hexavalent vaccines
• Concomitant administration with OPV may reduce the immune response to rotavirus vaccine; however, there is evidence that a high level of efficacy against severe gastroenteritis is maintained 
  • It is advised that 2 weeks should lapse between administration of the 2 vaccines

Other Rotavirus Vaccines

• Lanzhou lamb rotavirus vaccine
• Oral bovine rotavirus pentavalent vaccine
• Oral human neonatal rotavirus vaccine (RV3-BB)
  • A study in Indonesia showed that RV3-BB was efficacious in preventing severe rotavirus gastroenteritis when administered based on neonatal/infant immunization schedule in Indonesia
• Human attenuated rotavirus vaccine (G1P[8]) in lyophilized and liquid formulation