A Smallpox Shot in the Dark

[Guest guest]

OPINION

<A HREF= " http:// " >http://www.the-scientist.com/yr2002/jan/opin_020121.html</A>

A Smallpox Shot in the Dark

By Henry I.

Canamucio

------------------------------------------------------------------------

Sixty percent of Americans would opt for smallpox immunization if the vaccine

were available, according to a recent poll, and U.S. health officials have

just negotiated the purchase of enough vaccine for everyone in the United

States. Those two facts may be a prescription for bad medicine.Medically and

epidemiologically, smallpox is the most feared and potentially devastating of

all infectious agents. It spreads from person to person, primarily via

droplets coughed up by infected persons, via direct contact, and from

contaminated clothing and bed linens. Smallpox is fatal in approximately a

third of previously unvaccinated persons who contract the disease.

For weeks, the media have raised the specter of terrorists using smallpox

virus as a weapon. The German government has bought six million doses of

vaccine, and pressure is mounting in the United States for widespread, or

even universal, vaccination. (Routine smallpox vaccinations ceased in this

country in 1972.) The U.S. government has ordered 300 million doses of the

vaccine, and at a recent hearing, U.S. Sen. Arlen Specter (R-Pa.) said it is

just " common sense " to make it available to everyone who wants it.

But is it really? The live vaccine consists of live vaccinia virus, which is

closely related to smallpox virus. Impure and crude by the modern standards

of recombinant DNA-derived, or gene-spliced, vaccines such as those that have

been successfully deployed against hepatitis B since the 1980s, the smallpox

vaccine is not very different from the one introduced by the English

physician Jenner in the 18th century. It can provoke various serious

side effects, including rashes; spreading from the inoculation site to face,

eyelid, mouth or genitalia; and generalized infection. Approximately one in

every 300,000 vaccinations causes encephalitis, which can lead to permanent

neurological damage; and between one and three in every million die. Thus,

vaccinating the entire population would be expected to kill as many as a

thousand Americans, and maim and disfigure many others. Moreover, that

assumes that the newer, ostensibly incrementally improved versions of the

vaccinia vaccine are no less safe: Federal regulators have been

uncharacteristically lax about requiring evidence of safety and efficacy in a

drug intended for healthy individuals.

If the re-emergence of smallpox were likely, vaccination would be

appropriate. However, smallpox virus no longer occurs in nature but is

limited to two known, legitimate repositories, one in the United States, the

other in Russia (and perhaps to illegitimate ones in several other

countries). It is, therefore, very difficult to obtain, and also to cultivate

and disseminate.

Also, smallpox is not immediately contagious after infection. It can be

transmitted from one person to another only after a one- to two-week

incubation period and the appearance of the characteristic rash, by which

time the victim is prostrate, bedridden, and probably hospitalized.

Therefore, the much-publicized scenario in which suicide terrorists infect

themselves and then spread the disease widely through the population is not a

realistic one. And although universal smallpox vaccination was phased out

throughout the world during the 1970s, individuals who were vaccinated prior

to that time retain significant immunity from these immunizations, both

against contracting the disease and against a fatal outcome in case of

infection. Scientists know a great deal about the long-term retention of

immunity from a landmark study of 1163 smallpox cases in Liverpool in

1902-1903. Among those infected, 7% of the people 50 or older who had

received the vaccine as children experienced severe disease and death, while

26% of unvaccinated people in that age group contracted serious cases of

smallpox and all died.

Even if an outbreak were to occur, public health authorities know how to

respond. Control depends on early detection, quarantine of infected

individuals, surveillance of contacts, and focused, aggressive vaccination of

all possible contacts—an approach dubbed " quarantine-ring vaccination. "

Approximately 15 million doses of smallpox vaccine are available in the

United States, and data suggest that these would still be effective if

diluted fivefold, to yield 75 million.

Moreover, the federal government has taken steps to cope with the possibility

of a terrorist attack involving smallpox by educating doctors to recognize

the disease and by vaccinating small teams of experts who can rush to any

part of the country to confirm the diagnosis and contain and treat an

outbreak. The city of New York has begun to map out various locations where

residents would go to be immunized should mass vaccinations be necessary.

In summary, given the difficulty of estimating the risks and benefits of

vaccinating against a nonexistent disease using a vaccine that carries known,

serious, sometimes-lethal side effects, one must agree with the conclusion of

Busch, head of infectious diseases at California Pacific Medical Center

in San Francisco. " It's inappropriate " to vaccinate the entire country for a

disease whose threat is only theoretical, and immunization should only be

given " as needed, not as desired. "

If federal officials act otherwise, they will be more in the realm of public

relations than public health. Even the expenditure of upwards of a billion

dollars to stockpile 300 million doses of smallpox vaccine is arguably in the

category of political cover. Far better, surely, to use those resources to

ensure that susceptible Americans are immunized against common and

life-threatening infectious diseases such as influenza, hepatitis, and

pneumococcal pneumonia. (Flu alone kills 20,000 in an average year.)

Sherlock Holmes admonished in A Scandal in Bohemia that " it is a capital

mistake to theorize before one has data. " It is worse to make the wrong

decision after one has data.

Henry I. (<A HREF= " mailto:miller@... " >

miller@...</A>), MD, is a fellow at the Hoover Institution

and the author of To America's Health: A Proposal to Reform the Food and Drug

Administration (Hoover Institution Press).

------------------------------------------------------------------------

The Scientist 16[2]:64, Jan. 21, 2002

© Copyright 2002, The Scientist, Inc. All rights reserved.

We welcome your opinion. If you would like to comment on this article, please

write us at <A HREF= " mailto:editorial@... " >

editorial@...</A>