I am not learned in Vaccine Matters - but I think those look like Charley's Calves, Hablot Knight Browne

Object Type: watercolor painting. Dimensions: height: 54.6 cm (21.4 in) ; width: 73.3 cm (28.8 in). Medium: black chalk and watercolor, laid paper. Collection: Yale Center for British Art. Hablot Knight Browne - I am not learned in Vaccine Matters - but I think those look like Charley's Calves - B1993.30.47 - Yale Center for British Art