Could Zika Meet the Same Fate as Polio?

Nora details today how public health officials “have joined the political fight over emergency funding for efforts to stop the [Zika] virus.” In a press conference Monday, Anthony Fauci, the director of the National Institute of Allergy and Infectious Diseases, told reporters, “I don’t have what I need right now.”

As researchers scramble to develop a vaccine for the Zika virus, today marks an important anniversary in vaccine history: On April 12, 1955, researchers announced a vaccine for polio that was “safe, effective, and potent. Here’s a “News of the Day” clip from that day, posted by March of Dimes:

That vaccine, developed by Jonas Salk, led to the decline and the eventual eradication of the disease in the U.S. As the CDC notes, “the number of cases of paralytic poliomyelitis reported annually declined from more than 20,000 cases in 1952 to fewer than 100 cases in the mid-1960s.”

For the February 1957 issue of The Atlantic, Dr. David D. Rutstein, a professor at Harvard Medical School, analyzed the success of the Salk vaccine. He was careful not to overestimate its impact:

Summarizing the evidence through the autumn of 1956, we can draw the following conclusions:

The modified polio vaccine manufactured and distributed after November, 1955, has been safe for all practical purposes, but varies from batch to batch in its ability to produce protective substances.

The failure of this vaccine to prevent disease and at times death in certain vaccinated individuals and its apparent inability to reduce the number of carriers clearly indicate that polio will not be “wiped out” by this vaccine.

It is impossible to tell how much of the 1956 decrease in reported cases of polio in the United States is due to polio vaccination, but it is likely that some of it is due to the vaccine.

Rutstein pushed for more research:

Ann Hill “registers a startled expression”
upon receiving one of the first vaccine shots,
on April 18, 1955. (AP)

1. The polio immunization program should be expanded and continued as long as there is a continuing decrease in the number of reported cases of paralytic polio in the United States.

2. Any upswing in the number of such cases must demand a complete revaluation of the entire program.

3. To maintain a high level of protection in those successfully immunized with the present polio vaccine, it is imperative to determine when booster doses of vaccine will be necessary.

4. Lack of uniform potency of the present vaccine demands its improvement or the development of better “killed” or “living virus” vaccines.

We must maintain an objective attitude in the interpretation of results; we must not relinquish opportunities to improve on present methods and to utilize other means which may prove to be more effective in the conquest of polio.

Researchers went on to develop a more sophisticated vaccine, and today polio is far less of a threat worldwide: “The last case of wild-virus polio acquired in the United States was in 1979, and global polio eradication may be achieved within this decade,” according to the CDC.

Here’s hoping the fight to stop Zika has a similar conclusion.