The field of the invention relates to the use of carbohydrate binding compounds as a medicine, their use to treat or prevent viral infections, their use to manufacture a medicine to treat or prevent viral infections and their use in a vaccination strategy. The present invention relates to the use of said compounds to manufacture a medicine to treat or prevent viral infections of subjects, more in particular infections with viruses having glycosilated envelop proteins such as Retroviridae (i.e. Lentivirinae), like HIV (human immunodeficiency virus), Flaviviridae, like HCV (hepatitis C virus), Hepadnaviridae, like HBV (hepatitis B virus), Coronaviridae, like SARS corona virus, and Orthomyxoviridae, like influenza A, B or C.