Preventing Infection in the Community

PREVENTING INFECTION IN THE COMMUNITY

Prevention and control of infection in the community are goals shared by the CDC and state and local public health depart-ments. Much of public health emphasis is placed on prevention to avoid outbreaks and other situations that require control. Methods of infection prevention include sanitation techniques (eg, water purification, disposal of sewage and other potentially infectious materials), regulated health practices (eg, handling, storage, packaging, preparation of food by institutions), and im-munization programs. In the United States, immunization pro-grams have markedly decreased the incidence of infectious diseases.

Vaccination Programs

The goal of vaccination programs is to use wide-scale efforts to prevent specific infectious diseases from occurring in a popula-tion. Public health decisions about vaccine campaign implemen-tation efforts are complex. Risks and benefits for the individual and the community must be evaluated in terms of morbidity, mortality, and financial benefit.

The most successful vaccine programs are those for the pre-vention of smallpox, measles, mumps, rubella, chicken pox, polio, diphtheria, pertussis, and tetanus. Concerns that smallpox may be reintroduced as an act of biowarfare have led to a decision that medical first responders and selected others should again re-ceive small pox vaccine.

More than 25 vaccines are licensed in the United States. Vac-cines are made of antigen preparations in a suspension and are in-tended to produce a human immune response to protect the host from future encounters with the organism. No vaccine is com-pletely safe for all recipients. Some people are allergic to the anti-gen or the carrier substance. When live organisms are used as antigen, the actual disease (often with a modified course) may fol-low. Contraindications on package inserts of a vaccine must be heeded. These guidelines detail studied experience with allergy and other complications and provide crucial information about refrigeration, storage, dosage, and administration.

Variations to the recommended vaccination schedule should be made on a case-by-case basis, depending on the patient’s risk factors and ability to return for follow-up vaccinations at the ap-pointed time. For example, although the first dose of measles vac-cine is recommended at the age of 12 to 15 months, babies in developing countries (where measles contributes significantly to childhood morbidity and mortality) should be vaccinated at 9 months.

The standard recommended vaccination schedule for infants and children as developed by the CDC is shown in Table 70-2. The schedule is revised as epidemiologic evidence warrants, and nurses are advised to consult the CDC to determine the most recent schedule.

Vaccine recommendations for adults are designed to protect those with underlying diseases that increase infection risk, those with potential for occupational exposure, and those who may be exposed to infectious agents during travel. Immunosuppressed adults (including those who have had splenectomy) should be vaccinated for pneumococcus (Streptococcus pneumoniae), menin-gococcus (Neisseria meningitidis), and Haemophilus influenzae. Health care workers should be immune to measles, mumps, rubella, hepatitis B, and varicella. It is strongly recommended that all of the previously described adult groups and those with asthma or other chronic respiratory conditions receive annual influenza vaccine.

Information about individual vaccines or the most current vaccine schedules may be found on the Internet. The CDC also provides a 24-hour telephone hotline (800-232-2522) for information about routine pediatric or adult vaccine advice. Advice about op-timal vaccination for travelers is available on the Internet, by phone (877-FYI-TRIP), and by a toll-free fax number (888-232-3299) to request information.

Nurses should ask parents or adult vaccine recipients to pro-vide information about any problems encountered after vaccina-tion. As mandated by law, a Vaccine Adverse Event Reporting System (VAERS) form must be completed with the followinginformation: type of vaccine received, timing of vaccination, onset of the adverse event, current illnesses or medication, history of adverse events after vaccination and demographic information about the recipient. Forms are obtained by phoning 1-800-822-7967 or through the Internet.

The incidence of vaccine-preventable diseases, such as measles, mumps, rubella, and diphtheria, is affected by immigration from developing countries. Vaccine campaigns in developing countries are often financially and logistically constrained, and immigrants from such areas may be more likely than U.S. residents to be un-protected and may increase the potential pathways for epidemic spread. Individual risk and epidemic risk are reduced when vac-cination campaigns reach all communities, including those with a high proportion of immigrants.

CONTRAINDICATIONS

Patients who have experienced previous anaphylaxis or similar reactions; patients who have developed encephalopathy within 7 days of a previous diphtheria, tetanus, and pertussis (DTP) dose; and those who have developed other moderate or severe sequelae after a previous dose should not receive further doses. DTP is often deferred for the child who previously developed a fever higher than 40°C (104°F) within 48 hours of vaccination or who had a seizure or developed a shocklike state within 3 days of previous vaccination. Live vaccines usually are not indicated for patients or close contacts of patients with severe immuno-suppression (eg, HIV infection, leukemia, lymphoma, generalized malignancy, significant corticosteroid use, use of immuno-suppressive medications to prevent transplant rejection). The measles, mumps, and rubella vaccine should not be administered to pregnant women.

MEASLES, MUMPS, AND RUBELLA VACCINE

Since the measles, mumps, and rubella (MMR) vaccines were li-censed, reported cases of these diseases have decreased by more than 99% in the United States (ie, fewer than 500 cases per year since 1999). All public health departments are encouraged to vig-orously promote vaccination for all children and for susceptible adults unless contraindicated. Routine MMR vaccination should be given to children at 12 to 15 months of age, with repeat dosing at 4 to 6 years of age (Atkinson et al., 2002).

All who work in health care should demonstrate immunity to these three viruses by one of the following: birth date before 1957, documented administration of two doses of vaccine, laboratory evidence of immunity, or documentation of physician-diagnosed measles or mumps.

Side Effects.

Epidemiologic evidence supports that the risk forside effects is greater in nonimmune vaccine recipients than in those receiving repeat doses. Patients should be advised that fever, transient lymphadenopathy, or hypersensitivity reaction might occur. Antipyretics may be used to decrease the risk for fever, but aspirin should be avoided in infants and children because of the risk for Reye’s syndrome.

VARICELLA (CHICKENPOX) VACCINE

Varicella zoster is the causative viral agent of chickenpox and herpes zoster. In its natural state, the varicella virus attacks most individuals as children, causing disseminated disease in the form of chickenpox. Chickenpox is often more severe in adults. Transmission occurs by the airborne and contact routes. With rare exception, varicella infects an individual only once. 

The incubation period is about 2 weeks (range, 10 to 21 days). During a prodrome of general malaise (often noticed about 2 days before the rash develops), the newly infected host is capable of trans-mitting the virus to other susceptible contacts. Typically, the rash is vesicular and pustular and spreads rapidly from few to many le-sions in a matter of hours. New lesion formation continues for 2 to 3 days, with lesions appearing at different stages throughout this time. By the fourth symptomatic day, the lesions begin to dry, and new lesions usually do not develop. Fever is common during the 4 to 6 days of rash progression. When the lesions have crusted, the patient is no longer contagious to others.

Herpes zoster, also known as shingles, is a localized rash caused by recurrent varicella. Vesicles are restricted to areas supplied by single associated nerve groups. Varicella may be transmitted from the rash of those with shingles to people who are susceptible to varicella.

The varicella vaccine was first recommended as part of the routine vaccine schedule in the United States in 1996. The vac-cine is effective in preventing chickenpox in approximately 85% of those vaccinated and significantly reduces the severity in almost all those who get the disease despite vaccination (Atkinson et al., 2002). The vaccine should not be given to those who have de-pressed immune function, are pregnant, have received blood products in the past 6 months, or have demonstrated allergy to varicella vaccine.

INFLUENZA VACCINE

Influenza is an acute viral disease that predictably and periodically causes worldwide epidemics. Epidemics occur every 2 to 3 years, with a highly variable degree of severity. An average estimated ex-cess of 20,000 deaths per year have been attributed to influenza or its sequelae (ie, pneumonia and cardiopulmonary collapse) in vulnerable groups between 1977 and 1995 (Centers for Disease Control and Prevention [CDC], 2001d).

Each year, a new vaccine is available. It is composed of the three virus strains (usually two type A influenza and one type B influenza strains) considered most likely to occur in the coming season. When the presumed influenza agents have been correctly anticipated and included in that year’s vaccine, vaccine offers approximately 70% to 90% protection for healthy children and young adults. Although less effective in the elderly (as low as 30% to 40% in the frail elderly), it decreases the severity of illness in those who do get infected, is 50% to 70% effective in preventing pneumonia and hospitalization, and is 80% effective in prevent-ing death. In extended care facilities, risk of transmission is greatly reduced by vaccination of all residents (CDC, 2001d).

The Immunization Practices Advisory Committee of the Public Health Service recommends annual influenza vaccinations for the following groups at risk for influenza complications: those older than 50 years of age, residents of extended care facilities, those with chronic pulmonary or cardiovascular diseases, and those with diabetes, immunosuppression, or renal dysfunction. Vaccination is also advised for children (eg, those with juvenile rheumatoid arthritis) who require long-term aspirin therapy to reduce the likelihood of developing Reye’s syndrome. Health care providers and household members of those in high-risk groups should re-ceive the vaccine to reduce the risk of transmission to those vul-nerable to influenza sequelae. Vaccine campaigns among health care workers and patients should be intensified when there is evidence of community influenza disease.