we can focus research efforts on other critical issues: First, understanding the full spectrum of defects caused by congenital Zika virus infection; if Zika virus is similar to other teratogens, an expansion of the phenotype would be expected (e.g., with the congenital rubella syndrome, the phenotype was expanded from cataracts to include other findings such as hearing loss, congenital heart defects, and microcephaly).
11 Second, quantifying the relative and absolute risks among infants who are born to women who were infected at different times during pregnancy. Third, identifying factors that modify the risk of an adverse pregnancy or birth outcome (e.g., coinfection with another virus, preexisting immune response to another flavivirus, genetic background of the mother or fetus, and severity of infection). Addressing these issues will improve our efforts to minimize the burden of the effects of Zika virus infection during pregnancy.