Abstract: The present invention is directed to a method, i.e. an immunoassay, for determining the presence and/or the amount of anti-zika Anti-ZIKV #1 virus antibodies, i.e. zika virus-specific antibodies in a sample. Therefore, the present invention is directed to a microsphere complex comprising a microsphere coupled to a zika virus like particle, as well as to a kit comprising said microsphere complex and an amount of reporter antibody that binds to the zika virus like particle. The present invention further relates to a method for determining an antibody correlate of protection against zika virus infection for a zika virus vaccine. Moreover, the present invention is directed to a method for diagnosing the protection of a human or non-human subject against a zika virus infection.