CDC Panel May Advise Anthrax Shots for First Responders

Elaine Grossman
Global Security Newswire: Oct. 16, 2008

WASHINGTON - A U.S. government advisory panel next week could recommend that state and local public health officials consider administering anthrax vaccines to as many as 3 million first responders nationwide, Global Security Newswire has learned. The panel, convened by the Centers for Disease Control and Prevention, would leave it to regional and local authorities to determine whether the risks of biological terrorism - weighed against the potential benefits of a controversial inoculation - justify vaccinating emergency personnel.

In an anthrax attack, victims could inhale tiny airborne particles capable of infecting them with a highly fatal disease. The 2001 mailings that targeted congressional and media offices, launched just days after the Sept. 11 terrorist strikes, killed five people and sickened another 17 (see GSN <http://www.nti.org/d_newswire/issues/2008/10/1/5c85159e-7129-4ca0-b957-2fcc95aa144a.html > , Oct. 1).

The CDC panel decision, slated for release at an Oct. 22 meeting in Atlanta, could reverse a nearly 8-year-old recommendation against pre-exposure vaccinations for first responders. By contrast, U.S. military personnel operating in assignments considered at risk of exposure to anthrax attack have been subject to mandatory inoculation for several years (see GSN <http://www.nti.org/d_newswire/issues/2007/9/5/c0469347-f23c-4248-a063-c5a57ceafd57.html > , Sept. 5, 2007). While the compulsory program was suspended at one point under court order, the Defense Department has administered millions of shots since the late 1990s.

The CDC Advisory Committee on Immunization Practices said in December 2000 that it could not recommend anthrax shots for civilian first responders as a matter of national policy because "the risk of exposure cannot be calculated." Even if the threat were considered higher in one city or another, the panel concluded that precautionary vaccines were unnecessary. For emergency personnel who enter an attack site, "studies suggest an extremely low risk for exposure related to secondary aerosolization of previously settled [anthrax] spores," the group wrote at the time. If a first responder were exposed to anthrax, the "initiation of prophylaxis should be considered with antibiotics alone or in combination with vaccine," the panel concluded. Post-exposure treatment with these drugs is standard for unvaccinated patients.

In 2002, the panel updated other aspects of its anthrax vaccine recommendations but refrained from changing its guidance for first responders. However, at a meeting in Atlanta four months ago, a working group convened by the advisory committee said the full panel should alter its 2000 statement. "Post-event vaccination in combination with antibiotics is an effective intervention following exposure to [anthrax] spores, but the workgroup felt that pre-event vaccination could offer additional protection beyond that afforded by antibiotics and post-vaccination by providing early priming of the immune system," according to a CDC summary of the review group's presentation to the panel. In addition, some first-responder organizations "have stated that their members would be more willing to respond to a bioterrorism event if they were vaccinated prior to the occurrence of the event," working group member Jennifer Gordon Wright told the committee, according to the meeting summary. "The workgroup felt that implementing a recommendation for pre-event vaccination of first responders would be difficult, but it may have a positive impact on first-responder preparedness," she reportedly said.

If embraced by the expert panel next week, the new statement would read: "Groups for whom potential contact with aerosolized anthrax is a reasonable expectation based on occupation and duties (e.g. first responders expected to be called to the scene of a bioterrorism event) and for whom a calculable risk is not available may consider pre-event vaccination on the basis of an estimated risk benefit and in the context of an occupational health and safety program."

A Host of Challenges

Among the challenges facing any mass inoculation effort for first responders would be finding a method of tracking a complicated anthrax shot regimen for millions of personnel who might come and go from their jobs, according to the June meeting minutes. The schedule for the existing vaccine calls for six priming shots over an 18-month period, followed by annual boosters. Recent medical research suggests that fewer shots might be needed to establish immunity, but the official regimen has not yet changed (see GSN <http://www.nti.org/d_newswire/issues/2008/10/1/0ede5e29-59ab-4680-a2db-b1191e85f631.html > , Oct. 1).

Another hurdle could be organizing a vaccine campaign in the absence of any single organization representing the first-responder community nationwide, according to the June meeting summary. "There are multiple types of first responders and defining this group can be difficult," Wright told the CDC panel.

Litigation pending in federal court could pose another complication for state and local officials who might contemplate setting out a requirement that their first responders take the anthrax shots. Two attorneys who in 2004 won a 16-month injunction against the Pentagon's initial mandatory vaccine effort filed a second lawsuit in late 2006, challenging the science behind a 2005 Food and Drug Administration decision allowing the drug to be used for protection against an attack (see GSN <http://www.nti.org/d_newswire/issues/2004/10/28/54b0cd56-007b-42fc-b035-d2dcb3329d6e.html > , Oct. 28, 2004). They argue that the vaccine has been proven only in the prevention of anthrax contracted through the skin or digestive system, but has not been shown to work against a more serious form of inhaled anthrax posed by biological weapons.

The second case is now on appeal following a federal judge's move to dismiss it in late February (see GSN <http://www.nti.org/d_newswire/issues/2008/3/3/7228bc90-da71-477a-9828-92bfbe0725ed.html > , March 3). If the lawsuit moves forward in the U.S. Court of Appeals, "it would affect the current thinking of CDC and FDA" regarding the advisability of giving the vaccine to millions of first responders, said Mark Zaid, plaintiffs' co-counsel in both legal actions. The CDC advisory panel's working group reported in June that "available vaccine efficacy data suggested that the vaccine is effective and provides protection against inhalation anthrax." However, Zaid said state and local authorities should think twice before requiring the shots for emergency personnel, in the absence of a substantial threat. "It would be virtually unprecedented in modern times to mandate any vaccination on civilian populations without the clear existence of a current outbreak of disease," he told GSN yesterday.

Critics of the vaccine have alleged that officials at the Centers for Disease Control and Prevention - an arm of the U.S. Health and Human Services Department - have underemphasized the risk of severe adverse reactions carried by the anthrax vaccine. For example, a new CDC study of the anthrax vaccine's safety and efficacy logged 229 "serious adverse events" - including seven deaths - in 186 out of 1,563 volunteer participants receiving inoculations since May 2002. Such instances might include events that are life-threatening, require hospitalization or surgical intervention or cause significant disability or birth defects. Results were published in the Oct. 1 issue of the Journal of the American Medical Association.

However, the researchers concluded that just nine of these serious events - none resulting in death - were "possibly related" to the vaccine. Analysis of the research data will remain "double-blind" through next year, meaning the medical investigators and patients do not know which participants received anthrax inoculations and which received a placebo, according to CDC officials.

Until the serious-event data can be correlated with an understanding of which patients actually received the anthrax vaccine, an empirical analysis of the drug's safety in this study cannot be done, according to Meryl Nass, a longtime critic of the U.S. government's handling of the vaccine. An internist who has consulted with the U.S. government on bioterrorism issues, Nass questioned how CDC researchers could have concluded that just nine of the 229 serious adverse events might have been connected to the vaccine. In e-mail comments sent to GSN last week, she accused the agency of "glossing over" the severe reactions potentially related to the vaccine and of offering few details about them.

The working group's June presentation to the CDC advisory group identified vaccine safety as a possible issue for consideration in treating first responders, but voiced confidence in the research findings. "While the workgroup [members] believe the vaccine is safe, rare adverse events do occur and a serious adverse event is not a small matter, regardless of whether it is vaccine-associated," Wright told the panel, according to the CDC minutes.

The government advisory panel "has been given a one-sided picture from the working group at the CDC," Nass said in an interview this week. She rued the fact that few, if any, of the advisory panel's current members took part in the committee's debate nearly eight years ago, which resulted in its initial guidance against mass inoculations for first responders. This year, Nass said, the committee has heard nearly no critical perspectives about the safety and efficacy of the anthrax vaccine, and the group might similarly be unaware of skepticism about biowarfare threats facing the United States. The CDC panel has scheduled just five minutes of public comment about the issue during its upcoming meeting, she said.

A review of the committee's membership shows that none of the advisory panel's 15 voting members sat on the group in 2000, so there is little track record on which to base projections about how it will decide the issue this time. Eight liaisons from medical associations and industry organizations, "ex officio" members and others associated with the Advisory Committee on Immunization Practices served in similar roles in 2000, but none of them have a vote. Of the voting advisory panel members, several voiced support at the June meeting for making what they termed a "reasonable" change in the group's guidance regarding anthrax shots for first responders.

One of them, Jonathan Temte - a faculty member at the University of Wisconsin's School of Medicine and Public Health in Madison - said "allowing smaller [state and local] groups to consider their own risks is a very worthwhile approach," according to the CDC summary. Others expressed a degree of concern. For example, Franklyn Judson - a professor at the University of Colorado Health Sciences Center in Denver - said he would support the new statement but thought "practically it would do little at the local level," the summary states. Another, Ciro Sumaya of Texas A&M Health Center in College Station, "was uncomfortable with the wording" in the statement about assessing a risk-benefit tradeoff, adding that "there should be some type of algorithm to make risk determinations that can be useful to the practitioner and at the local level," according to the CDC minutes.