Pharmacists should become 'immunization advocates'
With concern rising about the possibility of an influenza pandemic, pharmacists must be immunization advocates and provide pharmaceutical care that includes evaluation of immunization status, according to a Pharmacotherapy article by two members of the U.S. Army Medical Command Military Vaccine Agency.
Stephen Ford, PharmD, and John Grabenstein, PhD, wrote that influenza epidemics occur each year and account for more illness in the developed world than all other respiratory diseases combined.
Pandemics occur when influenza viruses undergo either antigenic drift or antigenic shift that results in a new viral strain that infects humans, when they are capable of sustained transmission from person to person, and when they are introduced in populations with little or no pre-existing immunity. As many scientists have warned, an avian influenza A (H5N1) now circulating in Asia has pandemic potential, although no evidence currently exists that a pandemic is occurring.
Seasonal influenza infections and related complications result in some 36,000 deaths each year in the United States and between 3 million and 5 million severe flu cases worldwide, resulting in 250,000-500,000 deaths. So far, human H5N1 infection has involved 147 confirmed cases and 78 deaths, all in east Asia and Turkey.
No one knows for sure about avian flu
Although no one can yet say whether the next pandemic is imminent or even whether it will be caused by H5N1, pharmacists and other health care professionals have an obligation to evaluate current medical and scientific evidence, take inventory of available treatment and prevention interventions, and make rational treatment and prevention decisions focused on what is most beneficial now.
Ford tells Drug Formulary Review that immunization and sanitation are two of the most important achievements in controlling infectious diseases and improving public health. But he says this success is potentially at risk due to an expanding public focus on rare serious adverse events following immunization.
He recommends that pharmacists initiate practice changes including evaluation of immunization status/history as part of delivering pharmaceutical care. Pharmacists must understand basic immunization science and be well versed in immunization safety to effectively promote immunization and its importance in individual and public health. And pharmacists must work to improve immunization rates against vaccine-preventable diseases in vulnerable populations such as the elderly and children with chronic cardiopulmonary diseases. Pharmacists also must be immunized themselves.
According to Ford, hospitalized patients are often representative of the vulnerable populations and hospital pharmacists should actively promote immunization of hospitalized patients, if unprotected and not contraindicated, before hospital discharge or during follow-up appointments after an acute, serious illness has resolved.
Select populations at greatest risk
The risk of hospitalization and even death resulting from influenza complications is higher in people older than age 65, young children, and people of any age with certain underlying medical conditions including chronic disorders of the pulmonary or cardiovascular systems, including asthma; chronic metabolic diseases, including diabetes mellitus; renal dysfunction; hemoglobinopathies or immunosuppression; any condition that can compromise respiratory function or the handling of respiratory secretions or that can increase aspiration risk; and children or adolescents receiving long-term aspirin therapy. Influenza-related deaths often result from pneumonia or from worsening of underlying chronic disease. Effective influenza immunization programs that target high-risk people reduce the frequency of severe complications in vulnerable individuals.
The World Health Organization (WHO) has published recommendations for non-pharmaceutical public health interventions. The recommendations resulted from consultation with experts and evaluation of historic and current observations and data obtained from influenza disease models, as opposed to data from controlled studies. The authors said the effectiveness of individual measures will not be known until precise epidemiologic characteristics (attack rate, virulence, modes of spread within a community, affected age groups) of the pandemic virus are identified; thus, the WHO recommendations should be considered general guidance rather than formal WHO advice.
The WHO advice provides strategic guidance to limit international spread, including travel screening and restrictions. Unfortunately, according to the report, travel screening may have a limited impact because infected people may shed a virus before the onset of symptoms. Measures within affected communities include rapid case detection and isolation of infected people, contact tracing, quarantining those who are symptomatic, use of antivirals for treating cases and prophylaxis of others in the affected community, restrictions on movement and exit screening of people leaving the area where clusters of human cases are occurring.
Once a pandemic is declared, WHO may recommend any or all of these measures within affected countries: N95 respirator masks for health care workers and first responders, surgical masks for those seeking medical care, voluntary home confinement for people with fever and respiratory systems as well as their contacts, deferring non-essential domestic travel to areas with disease; travel health alerts for incoming travelers describing symptoms and giving instructions on where to report if symptoms develop, and for people with known exposure on an aircraft or cruise ship, consideration of daily fever checks and prophylactic antiviral treatment if available.
In a scenario in which all countries are affected, WHO recommends stopping patient isolation, contact tracing, and quarantining contacts because those measures no longer will be possible or useful. Additional recommendations include social distancing (such as closing schools and canceling events involving large gatherings or crowds), reinforcing hand hygiene, and reinforcing respiratory hygiene. The WHO does not recommend the general public wear masks, as this intervention would have negligible transmission impact.
Immunization remains the primary intervention for preventing severe influenza illness and its complications, the report says. No H5N1-specific vaccine has been licensed by FDA, although the National Institutes of Health, through the National Institute of Allergy and Infectious Diseases, and vaccine manufacturers are working on development and clinical investigation of H5N1 vaccines.
Ford wrote that because no surveillance evidence indicates that a pandemic is occurring now, and because the circulating H5N1 viral strain is not involved in sustained human-to-human transmission, it's not clear whether the H5N1 vaccine being developed would be protective in a future pandemic. "It is generally believed that this vaccine will provide at least partial protection in those immunized and serve as a bridge until a tailored pandemic vaccine could be developed," he says. "This 'priming' dose could be considered the first in a two-dose strategy much like seasonal influenza immunization in children younger than 9 years old not previously immunized against influenza. In such children, two doses one month apart are recommended to achieve adequate antibody response because they are unlikely to have ever encountered H1N1 or H3N2 influenza viruses earlier in life."
If a pandemic occurs before a vaccine is available, the article warns, substantial numbers of illnesses, hospitalizations, and deaths may occur. For that reason, public health control measures such as social distancing, use of respirator masks, isolation, and quarantine, and use of antiviral drugs would be the best available interventions to limit disease spread until adequate vaccine supplies become available.
Tamiflu is the only neuraminidase inhibitor licensed for prophylaxis of influenza in the United States, although several large, controlled, clinical trials have given evidence that both Relenza and Tamiflu are effective in preventing influenza illness among healthy adults, children, and high-risk elderly or chronically ill people. In those studies, both Relenza and Tamiflu were 70-90% effective in preventing illness either before or after exposure to influenza A or B viruses. Limited information is available documenting these drugs' effectiveness in human H5N1 infections.
Manufacturers have limited production ability
Limited production capacity among four major flu vaccine manufacturers — Sanofi Pasteur, Chiron, GlaxoSmithKline, and MedImmune — in combination with greater limitations on surge capacity, seriously limit the rate of pandemic influenza vaccine production, according to the article. Production and delivery delays of seasonal influenza vaccine that occurred last year dramatically emphasized the limitations. Also, regulatory requirements for evaluating new vaccine production methods such as cell culture and other nonegg-based techniques represent significant barriers to rapid pandemic vaccine development and production.
Ford says pharmacists are uniquely positioned to implement near-term interventions that may mitigate the impact of a future pandemic. Increasing the rates of pneumococcal and seasonal influenza immunizations in vulnerable populations may reduce the likelihood of severe influenza complications in the event of a pandemic. And increased seasonal influenza immunization rates or a universal immunization program resulting in increased market demand would prompt vaccine manufacturers to increase both influenza production and production capacity. Thus, in Canada, health officials negotiated a contract with the country's only domestic producer of trivalent influenza vaccine guaranteeing purchase of 5 million doses a year for the next 10 years. Ford says vaccine manufacturers respond to such demand by increasing production when less financial risk exists in an otherwise unpredictable vaccine market. "In addition," he says, "pharmacists and all health care professionals must become effective risk communicators. Public confidence in health officials and health care providers is often shaken when contradictory recommendations are made in the face of public health and other disease threats."
There are a number of levels of immunization advocacy that pharmacists can assume, Ford says. At a minimum, all pharmacists should ensure that vulnerable people are immunized against diseases that are the most significant sources of preventable mortality. That includes routine determination of immunization status and referral for recommended immunizations, identification of high-risk groups requiring targeted immunizations, and, most important, protecting themselves and those they come in contact with by being appropriately immunized. Pharmacists working outside a hospital can be immunization facilitators and host others who immunize. And consistent with state laws, pharmacists can become immunizers and assume an active role in protecting vulnerable people, recognizing that vaccine delivery by pharmacists is associated with higher immunization rates among those younger than age 65 receiving chronic drug therapy.
Ford cites a study comparing influenza immunization rates in states where laws permit pharmacists to administer immunizations compared with states without such legislation. The results indicated a statistically significant increase in influenza immunization rates in people ages 65 and older in states allowing pharmacist immunization. A positive result also was received from a pharmacist-managed immunization campaign that showed an increased influenza vaccination rate after the intervention (54% of patients) compared with baseline (28%) in high-risk patients identified through chart review.
Despite vaccine administration by a nurse in that campaign, Ford says, there is no reason to believe that a similar positive result would not be achieved if the pharmacists had administered the immunizations. The pharmacists in the campaign designed, initiated, implemented, and managed the logistics of the program to the point of immunization, including conducting intake surveys, providing disease and vaccine information, and resolving individual clinical issues, as well as providing clinic administrative oversight.
Pharmacists and other health care providers must be effective risk communicators, Ford says. Failure to communicate risks effectively may inadvertently increase public fears and undermine public confidence. Pharmacists must be trustworthy and authoritative sources for disease and drug information and communicate information in a way that empowers people to make informed and independent judgments about risks to their health and safety. That can range from dispelling myths about routine immunizations to communicating disease risk during a public health emergency such as a pandemic.
Ford concludes that if a pandemic virus reaches our communities, the best defenses will be local, with cities and counties effectively distributing vaccine and/or antiviral drugs, treating infected patients, and doing this efficiently and on an unprecedented scale. "If a pandemic virus attacks now, most cities and counties will have several months to prepare and progressively implement their responses," he says. "If, however, this virus waits a few more years, the national defenses will be considerably stronger."
[Editor's note: Contact Ford at (703) 681-5101, or e-mail Stephen.Ford@us.army.mil.]