Prevaccination Rotavirus Serum IgG and IgA Are Associated With Lower Immunogenicity of Live, Oral Human Rotavirus Vaccine in South African Infants.

BACKGROUND: Live oral rotavirus (RV) vaccines have shown modest efficacy among children in African countries for reasons that are not completely understood. We examined the possible inhibitory effect of preexisting antirotavirus antibodies on immunogenicity of monovalent RV vaccine (RV1). METHODS: Mother-infant pairs were enrolled at presentation for their routine immunization visit in Soweto, South Africa, when infants were aged 5-8 weeks. Infant serum samples were obtained before the first and second doses of RV1 and 1 month after the second dose. Maternal serum and breast milk samples were obtained prior to administration of each dose of RV1 to infants. RV-specific immunoglobulin G (IgG), IgA, and neutralizing activity in sera of infants and serum or breast milk samples of mothers were measured using enzyme-linked immunosorbent assays or a microneutralization test. RESULTS: Of the 107 serum pairs from infants who were seronegative for RV IgA at enrollment, we observed a strong positive association between IgG titers in pre-dose 1 sera of infants and mothers and significant negative associations between IgG titers in pre-dose 1 sera of infants and seroconversion to RV1 post-dose 1. Similarly, mothers whose infants' IgA seroconverted after RV1 had significantly lower pre-dose 1 IgG titers in sera than those whose infants did not seroconvert. CONCLUSIONS: High levels of preexisting serum IgG, including transplacentally acquired maternal IgG, appeared to have an inhibitory effect on the immunogenicity of RV1 among infants and may, in part, contribute to lower efficacy of RV vaccines in this and other low-income settings.

Introducing www.epidemic-em.org: A Collection of Online Resources and Training Materials for Strengthening use of Emergency Operations Centers for Epidemic Response.

OBJECTIVE: This work aimed to demonstrate that a website, www.epidemic-em.org, encompassing "static" resources, and videos, as well as other tools, can be used to strengthen public health emergency management capacity during epidemic response. METHODS: Existing resources were updated and developed for self-directed Emergency Operations Centers' capacity strengthening, in order to encompass current best practices, and to emphasize how public health emergency management concepts can support epidemic response activities. These materials formed the core of the website, launched in June 2020, to which country case studies were added. In 2021, a pilot virtual training program was designed using recorded video lectures and interviews with global experts in addition to the website material, which was delivered to South African responders. RESULTS: The website has been accessed in more than 135 countries, demonstrating widespread reach and interest in online and freely accessible materials to support public health emergency operations. Over 30 people participated in the pilot virtual training, and the evaluation showed improvement in knowledge, confidence in using emergency management concepts for epidemic response, and positive feedback on the virtual modality. CONCLUSIONS: Online tools can expand access to materials and resources for public health emergency management capacity strengthening. Virtual modalities can further serve as a powerful complement, and perhaps replacement, for traditional in-person technical assistance, despite some limitations.