
A fourth Covid-19 shot might be recommended this fall, as officials 'continually' look at emerging data
CNN
As the world approaches the second anniversary of the declaration of the Covid-19 pandemic by the World Health Organization, on March 11, more nations are rolling out -- or are discussing the possibility of -- fourth doses of coronavirus vaccine for their most vulnerable. In the United States, leading public health officials say they are "very carefully" monitoring if or when fourth doses might be needed.

The governments of Mexico and the United States signed a memorandum of understanding on Thursday to fund and expedite several wastewater treatment projects in the Tijuana River basin. Untreated wastewater continually affects residents living along the river, which flows across the border from Tijuana and through several of San Diego’s southern neighborhoods.