Human Rotavirus Vaccine RIX4414 (Rotarix™) Is Highly Efficacious in Infants from Asia During the First Two Years of Life

Safety of vaccines used for routine immunization in the United States: An updated systematic review and meta-analysis

BACKGROUND

Understanding the safety of vaccines is critical to inform decisions about vaccination. Our objective was to conduct a systematic review of the safety of vaccines recommended for children, adults, and pregnant women in the United States.

METHODS

We searched the literature in November 2020 to update a 2014 Agency for Healthcare Research and Quality review by integrating newly available data. Studies of vaccines that used a comparator and reported the presence or absence of key adverse events were eligible. Adhering to Evidence-based Practice Center methodology, we assessed the strength of evidence (SoE) for all evidence statements. The systematic review is registered in PROSPERO (CRD42020180089).

RESULTS

Of 56,603 reviewed citations, 338 studies reported in 518 publications met inclusion criteria. For children, SoE was high for no increased risk of autism following measles, mumps, and rubella (MMR) vaccine. SoE was high for increased risk of febrile seizures with MMR. There was no evidence of increased risk of  intussusception with rotavirus vaccine at the latest follow-up (moderate SoE), nor of diabetes (high SoE). There was no evidence of increased risk or insufficient evidence for key adverse events for newer vaccines such as 9-valent human papillomavirus and meningococcal B vaccines. For adults, there was no evidence of increased risk (varied SoE) or insufficient evidence for key adverse events for the new adjuvanted inactivated influenza vaccine and recombinant adjuvanted zoster vaccine. We found no evidence of increased risk (varied SoE) for key adverse events among pregnant women following tetanus, diphtheria, and acellular pertussis vaccine, including stillbirth (moderate SoE).

CONCLUSIONS

Across a large body of research we found few associations of vaccines and serious key adverse events; however, rare events are challenging to study. Any adverse events should be weighed against the protective benefits that vaccines provide.

6th World Congress of the World Society for Pediatric Infectious Diseases (WSPID)

The 6th World Congress of the World Society for Pediatric Infectious Diseases (WSPID) was held in Buenos Aires, Argentina between 18 and 22 November, 2009. This is one of the biggest pediatric infectious disease assemblies in the world and it brought together pediatricians and pediatric infectious disease and vaccine experts. Numerous topics about pediatric infectious diseases were discussed during the congress. The scientific program focused on vaccines and vaccine-preventable diseases, including epidemiological and vaccine efficacy trials and updates on topics of childhood infectious disease. We summarize the current knowledge about some childhood vaccines and vaccine-preventable diseases, including rotavirus vaccines, conjugated pneumococcal vaccines (PCV-7, PHiD-CV and PCV-13), varicella, pertussis meningococcal and pandemic H1N1 vaccines. The next WSPID congress will be held in Melbourne, Australia between 16 and 20 November 2011.

Update on Rotarix: an oral human rotavirus vaccine

Worldwide, rotaviruses are the single most important agents of severe gastroenteritis in infants and young children. Globally, it is estimated that every year rotavirus gastroenteritis causes more than 125 million episodes of diarrhea and nearly 527,000 deaths, mainly in developing countries. The development of new effective and safe rotavirus vaccines was recognized as the most effective intervention strategy that could yield a significant impact on the burden of rotavirus disease. Rotarix is an oral live-attenuated human rotavirus vaccine containing a single G1P[8] strain. The first oral dose may be administered as early as 6 weeks of age, with a minimum interval of 4 weeks prior to second dose; the vaccination course should be completed by the age of 24 weeks according to the manufacturer. In the USA, the upper age limit for the second dose has recently been recommended at 32 weeks of age by the Advisory Committee on Immunization Practices. The development program for Rotarix including Phase I, II and III multicenter studies involving over 100,000 infants has been established in Latin America, Europe, Asia and Africa. The vaccine proved to be well tolerated, immunogenic, efficacious, safe and not associated with intussusception. It provided 85-96% protection against severe rotavirus gastroenteritis caused by G1 and non-G1 serotypes in Latin American and European clinical trials; and of public health importance, Rotarix reduced hospitalizations of all-cause gastroenteritis by 40 and 75%, respectively. Efficacy against G2P[4] strains ranged from 41% in Latin America to 81% in Europe. In the former, Rotarix afforded sustained high protection (80.5%; 95% CI: 71.3-87.1) against severe rotavirus gastroenteritis during the first 2 years of life in a region with a changing pattern of wild-type rotavirus circulation. In a recently completed vaccine trial in South Africa and Malawi, Rotarix showed an overall efficacy of 61.2% (95% CI: 44.0-73.2) by 1 year of age. Although these rates are lower than those from developed and middle-income countries, they look promising given the lack of other effective interventions. With the expanding introduction of rotavirus vaccines into national immunization programs, postmarketing surveillance should be conducted to measure the impact of rotavirus vaccination, as well as continued monitoring of circulating rotavirus strains.

Rotarix: a rotavirus vaccine for the world

Single rotavirus infections have been reported to protect humans against subsequent illnesses caused by both homotypic and heterotypic rotaviruses. On the basis of these observations, a G1P[8] strain of human rotavirus named 89-12 was attenuated by multiple passages in cell culture and was developed into a vaccine candidate (herein referred to as the RIX4414 vaccine). This vaccine is currently licensed in >100 countries worldwide, many of which have a universal recommendation for all infants. The US Food and Drug Administration approved the RIX4414 vaccine for use in the United States in April 2008. This vaccine has been found to provide a reduction in the incidence of severe rotavirus disease of >80% in all trials including a developing country. No increased risk of intussusception has been associated with this vaccine, nor has the vaccine been found to interfere with responses to other routine immunizations. This article describes the history of the development of the RIX4414 vaccine.