DES MOINES — Gov. Kim Reynolds on Friday urged Iowans to stay vigilant in their efforts to keep coronavirus in check and prevent a resurgence in COVID-19 infections that forced her to close schools, businesses and many activities for about 11 weeks earlier this year.“Now is not the time to let our guard down,” Reynolds said in an open letter to Iowans she issued roughly five months after the coronavirus pandemic arrived in the state in March.“Iowa has a lot to gain by working together to keep our communities healthy.