The present invention relates to short chain fatty acids (SCFA) for use in transmucosal administration to a subject for the prevention, attenuation or treatment of a disease or disorder associated with a compromised Th1 immune response and/or an unwanted Th2 or Th2-like immune response by modulating a Th2 immune response towards a Th1 immune response, particularly for the treatment, prevention and/or amelioration of viral infections and as an adjuvant for promoting the efficiency of vaccines and/or prevention of allergic diseases or disorders.