On Wednesday, the World Health Organization (WHO) declared the Zika virus as a health emergency of international concern. The designation, also used by WHO during the outbreaks of H1N1 and Ebola, allows more funding to flow to study and fight the disease, which WHO said moved “explosively” through South America. Zika virus is spread when the Aedes aegypti mosquito bites an infected human and transfers the virus when it feeds again. If symptoms present themselves, the rash, fever, joint pains are mild enough that the infected person doesn’t need to visit the hospital. But because the Aedes aegypti mosquito also lives and feeds in the southern United States, U.S. media has issued fact sheets about the virus and instructions on how not to get bitten. Zika is a concern because it is strongly suspected for causing the once-rare birth defect microcephaly and it’s not well understood. Currently, there are about 4,000 suspected cases of microcephaly in Brazil.

Look at the numbers, though, and the Zika virus isn’t cause for wide concern. Scientists are saying that there could be as many as three to four million people infected over the course of the next year in the Americas, which, as of 2013, had a population of 953.7 million. Four million represents just 0.4194% of that population. And 80% of those affected will never exhibit any symptoms. The birth rate in the Americas is 15.6 million people per year. Assuming an even distribution of infections across the population, that represents 65,426 pregnant women that could be infected — a mere .00686% of the population of the Americas. But, by all means, let’s panic.