Viral hepatitis, type B (MS-2) was prevented by active and passive immunization. Active immunization was induced by inoculation of a boiled, inactivated preparation of a 1:10 dilution of MS-2 serum in distilled water; two inoculations at four-month intervals were more effective than one. However, one inoculation gave enough protection to prevent some cases and modify others.
Krugman S, Giles JP, Hammond J. Viral Hepatitis, Type B (MS-2 Strain)Studies On Active Immunization. JAMA. 1971;217(1):41-45. doi:10.1001/jama.1971.03190010023005