To Protect the Unborn

One by one, the diseases that have crippled or slaughtered children through the ages are yielding to preventive vaccines -- first smallpox, then diphtheria, whooping cough, polio, and most recently, measles. Last week the U.S. Government approved a vaccine that will benefit no child already born, but is expected to save hundreds of thousands of unborn infants from death or dis abling malformations in the womb. It is a vaccine to protect against German measles, folk-named "three-day measles" and technically rubella. The first ship ments were on their way to doctors with in hours of the licensing announcement.

Long Unsuspected. For virtually every human being outside the womb, rubella is a trivial complaint. It usually causes a mild fever, a fleeting rash, a slight headache, occasionally a cough and a sore throat. Some cases are so mild that they pass unnoticed, yet all apparently confer lifelong immunity. Unlike mumps and common measles, rubella seldom evokes severe ill ness in the 20% of people who escape it in childhood and catch it as adults.

It reserves its killing and brutally deforming powers for the most helpless of all, those most recently conceived.

Rubella's cause and effect were long unsuspected. Not until 1941 did an Australian ophthalmologist, Sir Norman McAlister Gregg (1892-1966), discover that an unusual number of his infant patients, born with cataracts, had been conceived during a 1940 rubella epidemic.

Doctors then began to recognize many other birth defects resulting from maternal rubella, including abnormalities in the heart, limb deformities, deafness and mental retardation. Such damage occurs in about 50% of fetuses whose mothers had rubella during their first six months of pregnancy.

Rubella flourishes among youngsters who are crowded together in kindergartens and the lower grades of school.

Mothers are apt to catch it from them, like the common cold, through nose and mouth. It builds up to epidemic pro portions every five to seven years. The last U.S. epidemic, in 1964, caused 15,000 to 20,000 spontaneous abortions and stillbirths. It left an equal number of children with incurable and for the most part uncorrectable defects, from blindness and total deafness to imbecility. Its ravages in the U.S. alone were more terrible than the worldwide effects of the more highly publicized thalidomide disaster, which left 8,000 chil dren deformed. Epidemiologists feared that the next round, predicted for 1970-71, would be equally savage.

The beginning of the end for rubella came in 1961, when two groups of investigators, one headed by Dr. Thomas Weller at Harvard, the other led by Dr. Paul D. Parkman at the Walter Reed Army Institute of Research, isolated the virus and devised ways of cultivating it in the laboratory. Parkman and a fellow pediatrician, Dr. Harry M. Meyer Jr., subsequently teamed up to attenuate or "tame" the virus so that, in a vaccine, it would cause no disease but would still trigger the making of antibodies and thereby produce immunity. Their strain, which was dubbed HPV-77, is the basis of the vaccine now licensed.

They also developed a relatively simple blood test to show whether an individual has already had rubella and does not need the vaccine because he is immune.

Herd Immunity. Merck Sharp & Dohme researchers, after a false start with a virus strain of their own, adopted HPV-77 and further refined it in cultures of cells from duck embryos. Three other U.S. pharmaceutical houses took their own tacks in the competition for a market worth at least $100 million in the next few years. The first rubella vaccine licensed anywhere in the world was a Belgian product, approved in Switzerland in April and taken over for U.S. marketing by Smith Kline & French Laboratories. Last week, the Department of Health, Education and Welfare licensed only the Merck product, but approvals for one or two more were expected to follow.

Merck had 650,000 doses ready for shipment, promises 2,000,000 by August and expects to produce 18 million doses within a year. The cost to doctors is expected to be about $2.50 for the individual vial of vaccine, which must be injected.

The question bedeviling public health authorities in the U.S. and elsewhere is: Who should get the vaccine first? It would seem logical to vaccinate women who are likely to become pregnant and whose blood tests show that they have no immunity. This is essentially what the British plan to do when they license a vaccine. But HEW concluded that it is too hard to sort out susceptible women from the immune. Moreover, if a woman were already pregnant when vaccinated, or conceived within a few weeks, even the weakened vaccine virus in her bloodstream might damage her fetus.

The principle of "herd immunity," which has worked well against both polio and common measles, will be applied instead. The U.S. Public Health Service's recommendation to both private and public health doctors is to vaccinate all children from age one up to puberty, with the goal of immunizing virtually all of the 50 million in this age bracket within a few years. The effect would be to dry up the reservoir of susceptible youngsters.

Only in carefully managed individual cases, says HEW, should a woman in her child-bearing years get the vaccine. Then her doctor should give it only if she has been shown by blood test to be susceptible, and can be proved not to be already pregnant. She must also be willing to use a reliable contraceptive for three months to guard against possibly harmful effects from the vaccine virus. These rules may prove difficult to enforce as women demand the vaccine. But within a few years, rubella-damaged babies should be as rare as new victims of paralytic polio or of measles encephalitis have become since vaccines tamed those diseases.

* A totally different disease, caused by an unrelated virus, is the "red" or "seven-day" measles, which doctors call rubeola.

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