RE: Seroprevalence of Zika virus among asymptomatic pregnant mothers and their newborns in the Najran region of southwest Saudi Arabia

To the Editor: We read the publication on “Seroprevalence of Zika virus among asymptomatic pregnant mothers and their newborns in the Najran region of southwest Saudi Arabia” with a great interest.1 Alayed et al found that “Twenty-four (5.85%) mothers tested positive for anti-ZIKV IgM and 52 (12.68%) tested positive for anti-ZIKV IgG, but all infant samples were negative.”1 In fact, in any area where the mosquito vector exists (Aedes aegypti), there is a risk for Zika virus disease. A high positive seroprevalence rate is reported from many areas around the world despite there being no overt clinical cases. A good example is a report from Cambodia where many local people have immunoreactivity to Zika virus despite there being no clinical disease.2 Indeed, most cases of Zika virus infection are asymptomatic3 and this is the difficulty in clinical surveillance of the emergence of the disease in any setting