Examination of the Safety of Pediatric Vaccine Schedules in a Non-Human Primate Model: Assessments of Neurodevelopment,Learning, and Social Behavior

Background

In the 1990s, the mercury-based preservative thimerosal was used in most pediatric vaccines. Although there are currently only two thimerosal-containing vaccines (TCVs) recommended for pediatric use, parental perceptions that vaccines pose safety concerns are affecting vaccination rates, particularly in light of the much expanded and more complex schedule in place today.

Objectives

The objective of this study was to examine the safety of pediatric vaccine schedules in a non-human primate model.

Methods

We administered vaccines to six groups of infant male rhesus macaques (n = 12–16/group) using a standardized thimerosal dose where appropriate. Study groups included the recommended 1990s Pediatric vaccine schedule, an accelerated 1990s Primate schedule with or without the measles–mumps–rubella (MMR) vaccine, the MMR vaccine only, and the expanded 2008 schedule. We administered saline injections to age-matched control animals (n = 16). Infant development was assessed from birth to 12 months of age by examining the acquisition of neonatal reflexes, the development of object concept permanence (OCP), computerized tests of discrimination learning, and infant social behavior. Data were analyzed using analysis of variance, multilevel modeling, and survival analyses, where appropriate.

Results

We observed no group differences in the acquisition of OCP. During discrimination learning, animals receiving TCVs had improved performance on reversal testing, although some of these same animals showed poorer performance in subsequent learning-set testing. Analysis of social and nonsocial behaviors identified few instances of negative behaviors across the entire infancy period. Although some group differences in specific behaviors were reported at 2 months of age, by 12 months all infants, irrespective of vaccination status, had developed the typical repertoire of macaque behaviors.

Conclusions

This comprehensive 5-year case–control study, which closely examined the effects of pediatric vaccines on early primate development, provided no consistent evidence of neurodevelopmental deficits or aberrant behavior in vaccinated animals.

Citation

Curtis B, Liberato N, Rulien M, Morrisroe K, Kenney C, Yutuc V, Ferrier C, Marti CN, Mandell D, Burbacher TM, Sackett GP, Hewitson L. 2015. Examination of the safety of pediatric vaccine schedules in a non-human primate model: assessments of neurodevelopment, learning, and social behavior. Environ Health Perspect 123:579–589; http://dx.doi.org/10.1289/ehp.1408257     

Selecting US research-intensive doctoral programs in nursing: Pragmatic questions for potential applicants

Nurses hoping to enter a research intensive doctoral program have a choice of program delivery modes, faculty expertise, and multiple points of entry in addition to the traditional post masters. The American Association of Colleges of Nursing (AACN) lists doctoral programs in nursing in over 300 universities in the United States (U.S.) and Puerto Rico, with most institutions offering more than one type of doctorate. For prospective students who want to maximize their likelihood of significant, sustained scientific impact, identifying research-intensive Doctor of Philosophy (PhD) programs with faculty who have a topic match is key. Embarking on a scientific career requires assessing the curricula and faculty at several institutions. The purpose of this paper is to give prospective students pragmatic guidance in selecting a U.S. research-intensive doctoral program in nursing. We provide a list of published quality indicators in PhD programs as well as potential questions to be addressed to key persons in schools.     

Evaluation of direct thrombin inhibitors during a critical heparin shortage

Journal of Thrombosis and Thrombolysis - A recent heparin shortage related to an outbreak of African Swine Flu in China led to substantial increase in the use of direct thrombin inhibitors (DTI) as...