1171. Measles and Rubella Seroprevalence among HIV-infected and uninfected Children and Adults in Zambia

Abstract Background Despite the availability of safe and effective vaccines, measles and congenital rubella syndrome remain important causes of morbidity and mortality. HIV-infected individuals may be more vulnerable to measles because of poor immune responses to vaccination. Population-level estimates and comparisons of measles and rubella seroprevalence between HIV-infected and uninfected children and adults in sub-Saharan Africa are needed to guide vaccination policy and control strategies. Methods This cross-sectional study was performed by analysing a selected and weighted subsample from the Zambia Population HIV Impact Assessment survey (ZAMPHIA). ZAMPHIA was conducted in 2016 to estimate national HIV incidence and prevalence in Zambia. Dried blood spots and plasma samples were tested for IgG antibodies to measles and rubella viruses using a commercial enzyme immunoassay. We estimated national age-specific measles and rubella seroprevalence by HIV infection status using hierarchical generalized additive models. Results Specimens from 9521 HIV-uninfected (3840 children age under 10 years, 3981 youth age 10-19 years, and 1700 adults age 20-49 years) and 331 HIV-infected (53, 107, and 171 respectively) individuals were included in the study. Measles seroprevalence was lower among HIV-infected children (46.4%) compared to HIV-uninfected children (76.4%, p < 0.001). In both HIV-uninfected and HIV-infected individuals, measles seroprevalence increased steadily with age but more rapidly in the HIV-infected until about the age of 20 years when the seroprevalence was similar between the two groups. Above 20 years, measles seroprevalence was similar between HIV-infected and uninfected adults. There was no significant difference in rubella seroprevalence between HIV-infected and HIV-uninfected individuals. Figure 1. Measles and Rubella Age-specific Seroprevalence The lines represent generalized additive model fits for the mean (solid) and 95% confidence intervals (dashed). Data are grouped by age in years and year 0 includes only specimens from children 9-11 months. Rubella-containing vaccine was not available in the public sector prior to the serosurvey. Conclusion Measles seroprevalence was lower among HIV-infected than uninfected children and youth. HIV-infected children would likely benefit from revaccination. Many children were susceptible to rubella before the introduction of the combined measles and rubella vaccine in Zambia. Disclosures Kyla Hayford, PhD, MA, Pfizer, Inc. (Other Financial or Material Support, KH conducted the study and analyses while working at the Johns Hopkins School of Public Health but is an employee at Pfizer, Inc. as of 26 October 2020.)


Session: P-69. Pediatric Vaccines
Background. Rotavirus causes 215,000 deaths from severe childhood diarrhea annually. Two rotavirus vaccines -a monovalent vaccine containing a single rotavirus strain (RV1) and a pentavalent vaccine containing 5 rotavirus strains (RV5) -are used in routine immunization programs of nearly 100 countries. Concerns exist that rotavirus vaccines may be less effective against rotavirus strains not contained in the vaccines which could subsequently cause selective pressure and strain replacement. We estimated the vaccine effectiveness (VE) of RV1 and RV5 against vaccine (homotypic) and non-vaccine (partially and fully heterotypic) strains.
Methods. After conducting a systematic review, we meta-analyzed 31 case-control studies (N=27,293) conducted between 2006 and 2020 using a random-effect regression model.  Figure 1). Strain-specific RV5 VE differences were less pronounced ( Figure 2). Limited data were available from low-income countries.  Conclusion. Vaccine effectiveness of RV1 and RV5 was somewhat lower VE against non-vaccine than vaccine strains. Ongoing surveillance is crucial to continue long-term monitoring for strain replacement, particularly in low-income settings where data are limited.

Results
Disclosures. All Authors: No reported disclosures Background. Despite the availability of safe and effective vaccines, measles and congenital rubella syndrome remain important causes of morbidity and mortality. HIV-infected individuals may be more vulnerable to measles because of poor immune responses to vaccination. Population-level estimates and comparisons of measles and rubella seroprevalence between HIV-infected and uninfected children and adults in sub-Saharan Africa are needed to guide vaccination policy and control strategies.

Measles and Rubella Seroprevalence among HIV-infected and uninfected Children and Adults in Zambia
Methods. This cross-sectional study was performed by analysing a selected and weighted subsample from the Zambia Population HIV Impact Assessment survey (ZAMPHIA). ZAMPHIA was conducted in 2016 to estimate national HIV incidence and prevalence in Zambia. Dried blood spots and plasma samples were tested for IgG antibodies to measles and rubella viruses using a commercial enzyme immunoassay. We estimated national age-specific measles and rubella seroprevalence by HIV infection status using hierarchical generalized additive models.
Results. Specimens from 9521 HIV-uninfected (3840 children age under 10 years, 3981 youth age 10-19 years, and 1700 adults age 20-49 years) and 331 HIVinfected (53, 107, and 171 respectively) individuals were included in the study. Measles seroprevalence was lower among HIV-infected children (46.4%) compared to HIVuninfected children (76.4%, p < 0.001). In both HIV-uninfected and HIV-infected individuals, measles seroprevalence increased steadily with age but more rapidly in the HIV-infected until about the age of 20 years when the seroprevalence was similar between the two groups. Above 20 years, measles seroprevalence was similar between HIV-infected and uninfected adults. There was no significant difference in rubella seroprevalence between HIV-infected and HIV-uninfected individuals. The lines represent generalized additive model fits for the mean (solid) and 95% confidence intervals (dashed). Data are grouped by age in years and year 0 includes only specimens from children 9-11 months. Rubella-containing vaccine was not available in the public sector prior to the serosurvey.
Conclusion. Measles seroprevalence was lower among HIV-infected than uninfected children and youth. HIV-infected children would likely benefit from revaccination. Many children were susceptible to rubella before the introduction of the combined measles and rubella vaccine in Zambia.
Disclosures. Kyla Hayford, PhD, MA, Pfizer, Inc. (Other Financial or Material Support, KH conducted the study and analyses while working at the Johns Hopkins School of Public Health but is an employee at Pfizer, Inc. as of 26 October 2020.) Background. SARS-CoV-2 vaccine hesitancy (VH) is hindering nationwide vaccination efforts; little is known about caregiver SARS-CoV-2 vaccine acceptance for children. We aimed to identify associations with SARS-CoV-2 VH in caregivers of hospitalized children.

SARS-CoV-2 Vaccine Hesitancy in Caregivers of Hospitalized Children
Methods. We conducted a prospective cross-sectional survey in English and Spanish of caregiver COVID-19 knowledge, attitudes, behaviors, and associated VH among hospitalized children 6 months -18 years at a large pediatric medical institution. Parents were approached daily, averaging 4-5 days/week, from 12/8/2020--4/5/2021. VH was assessed using the Parent Attitudes about Childhood Vaccines (PACV) survey; PACV score ≥50 denoted VH. Descriptive statistics and multivariable logistic regression were used. Responses were categorized.
Results. 295/307 (96%) of approached caregivers enrolled; 79% were ≥ 30 years, 68% were married/ living with a partner, and 57% had at least some college. 36% identified as white, 19% Black, and 46% Hispanic/ Latino. 53% of caregiver children had public insurance. 91% of caregivers self-reported their children were up to date with routine vaccines. 17% of caregivers were vaccine-hesitant overall. 50% of caregivers were willing to receive COVID-19 vaccine themselves. Figure 1 shows intention to vaccinate their child by PACV score.
65% knew someone who was hospitalized for COVID-19. 67% were scared of their child getting COVID-19. However, 49% were scared of their child getting the vaccine, 28% did not want to vaccinate their child and 27% were neutral in the intention to vaccinate their child. Caregivers who did not intend to vaccinate their child were more likely to be Black (27% vs. 16%, p=0.04) and less likely to be Hispanic/ Latino (33% vs. 49%, p=0.02). Table 1 shows attitudes, beliefs, and behaviors surrounding the COVID-19 pandemic and vaccine in caregivers who did or did not intend to vaccinate their child. COVID-19 vaccine uptake by PACV score Table 1 Caregiver attitudes, beliefs, and behaviors surrounding the COVID-19 pandemic and the COVID-19 vaccine Conclusion. The majority of caregivers believe that SARS-CoV-2 vaccine will help control the pandemic, but less than half plan to vaccinate their children. A quarter of caregivers expressed uncertainty regarding the vaccine and therefore may be amenable to education and discussion. COVID-19 VH is different from VH towards routine vaccinations. More research is needed to address COVID-19 specific VH. Background. Higher valency pneumococcal conjugate vaccines (PCV10 and PCV13) replaced PCV7, and an updated global analysis of PCV impact on invasive pneumococcal disease (IPD) incidence is needed. We aimed to estimate the change in