VACCINE PROGRESS

Medical science has produced no drugs to cure or even treat diseases caused by the small, true viruses. Man's only defense against them is preventive warfare waged with vaccines. But newly won knowledge is broadening and intensifying this prophylactic attack on 14 major and minor diseases. Current status and prospects:

Smallpox. Improved vaccines are being made, some by growing cowpox virus in live calves (the historic method), some in chick embryo, freeze-drying it so that it will ship better and keep longer without refrigeration.

Chicken Pox. Essentially the same virus also causes shingles. First grown in test tubes in 1953 in John F. Enders' lab by Dr. Thomas Weller, who has since devised diagnostic tests, hopes for future preventives.

Measles. Widespread testing in many countries of several variant vaccines; good prospects for choosing a safe and effective one within two years.

Herpes Simplex ("fever blisters," many "canker sores"). Grown in tissue culture, but no vaccine in sight. Smallpox vaccine sometimes used in severe cases.

Mumps. Moderately effective killed-virus vaccine available, used mainly for military recruits and pregnant women; several labs working on improved and live-virus forms.

Influenza. Various virus subtypes cause the disease, so need is for a general-purpose vaccine. Lederle Laboratories' civilian vaccine combats four strains, including Asian. Manufacturers say Public Health Service delayed too long in warning of probable outbreaks this fall and winter, so output has fallen behind need. Demand is high; black markets might develop. Made from viruses grown in incubating eggs and killed with formaldehyde, flu vaccine gives only moderate, far-from-permanent immunity. No major improvement in prospect. Russia, despite setbacks, is trying to perfect an influenza vaccine that can be inhaled or swallowed.

Yellow Fever. Vaccine is already near-perfect.

Dengue ("breakbone fever"). Vaccine was made at World War II's end against the only virus then recognized; now it is known that at least four types are involved, with geographic overlaps. Work in progress on an all-type vaccine.

Encephalitis (arborvirus-caused brain inflammation, more prevalent in Asia and Europe than in U.S.). Vaccines to date have been unsatisfactory or actually dangerous for man. Work is in progress on virus found in Malayan rodents in hopes that its protein overcoat will prove to be of a basic pattern that will trigger formation of antibodies against several close-kin viruses.

German Measles (rubella). Work goes on in several labs, including Enders', to get this unclassified virus to grow in tissue cultures. Since the illness in children is so mild, the raw virus could probably be used to infect girls before puberty; the danger is that if they escape childhood infection, exposure during the first three months of pregnancy may cause crippling or fatal damage to the fetus.

Rabies. Improved vaccine, including some from virus grown in incubating duck eggs, has eliminated much of the pain and danger of old-fashioned "Pasteur treatment."

Infectious Hepatitis. Disease is on the rise, will probably have caused a record 70,000 cases in the U.S. by the end of 1961. Parke, Davis virologists have tissue-cultured what may be only one of several virus subtypes. Attenuated strains give varying protection, as measured in prison volunteers. At least two years before a generally useful vaccine can be made.

Paralytic Polio. The Salk killed vaccine gives good protection, provided that all the shots are full strength; duration of protection not yet certain'. Dr. Albert Sabin's three attenuated strains have been given by mouth to almost 100 million people in Russia, to more than a million in the U.S.; Sabin vaccines containing Type I and Type II strains have been approved by PHS for general prescription use, but safety standards are so high that Type III will be delayed until 1962. Dr. Sabin favors giving three separate doses, spaced three to four weeks apart. Lederle Laboratories' Dr. Herald R. Cox developed a one-swallow live-virus vaccine that was given to 418,000 people in Dade County (around Miami) in 1960; for the last 18 months the county has had not one case of polio, nor have health officials been able to find poliovirus in sewage. Live-virus vaccines such as Sabin's and Cox's protect the entire body by preventing poliovirus multiplication in the intestinal tract; Salk's killed vaccine lets virus into the intestinal tract, but protects the nervous system by blocking the virus' escape from the blood thus preventing paralysis.

Common Cold. Britain's Sir Christopher Andrewes found, thanks to a laboratory accident, how to grow many strains of common cold viruses in cultures with acidity and temperature approximating those in the human nose. There are at least 20, perhaps 40. To do much good, a vaccine would have to combine several of the commonest strains. Then it will remain to be seen how long the immunity lasts even against these strains. A useful vaccine against the common cold is years away.

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