Health & Medical Infectious Diseases

Infection Prevention and Control in Residential Facilities

Infection Prevention and Control in Residential Facilities

Appendix B: Vaccines

Background


How Vaccines Work. Vaccines prime the immune system against future "attacks" by a particular germ or infectious agent (bacteria or virus) that can cause serious disease. The goal is for the vaccine to imitate what happens when the body sees the actual germ but without causing illness. Vaccines may be made from killed bacteria or viruses, weakened (attenuated) viruses, or a substance produced by bacteria (toxin, protein, or polysaccharide antigen). The material in the vaccine is not strong or plentiful enough to make the recipient sick, but it is enough to cause the immune system to produce antibodies. As a result, future immunity is developed against the disease without getting sick. If one is reexposed to the infectious agent, the immune system will recognize and fight it. In some instances, vaccines may provide better immunity than the natural infection.

Impact of Vaccines. The development and delivery of vaccines is cited as one of the 10 most important public health accomplishments of the 20th century because of the dramatic prevention of illness, disability, and death from several infections. Examples of the enormous impact that vaccines have had on health in the United States are summarized in Table B1. The numbers of cases of disease and death that have been prevented is extraordinary, and business analyses demonstrate the economic benefit of vaccination. A recent study indicates that vaccinating every child born in the United States prevents approximately 42,000 deaths and 20 million cases of disease. It has been shown with several vaccines that the rate of disease drops dramatically when the vaccine is introduced and, if use is suspended for cost or safety reasons, the disease returns. The reasons why recommended vaccines are provided to all children and adults are summarized in Table B2.

Vaccine Safety. Since families no longer encounter diseases such as polio, measles, and bacterial meningitis, they do not appreciate the threat that these diseases pose to children and communities. At the same time, there has been much information in newspapers and on the Internet about potential side effects of vaccines. While some information is accurate, much of it is not, and this may cause unnecessary fear among parents. It is important to understand the dedication of vaccine manufacturers, professional organizations that develop recommendations, and individual providers to assuring the safety of recommended vaccines. There are several stages at which vaccine safety is determined that are summarized in Table B4. Some of the more recent safety questions that have been answered include the following.

1. The potential role of mercury and other chemicals in vaccines in causing autism has been disproven. When this suspicion arose, thimerosal, the mercury-containing preservative in some vaccines, was removed in 1999. However, after many comprehensive studies, it was determined that ethyl mercury, the formulation of mercury that was in the preservative, is eliminated from the body rapidly, is not detected in the brain, and certainly does not cause autism. In contrast, methyl mercury, the form of mercury that is present in the environment (eg, certain fish), is retained in the body. Nevertheless, mercury is not present in currently available vaccines.

2. The role of vaccines themselves in causing autism has also been disproven. Similarly, many studies of autism and vaccines have been completed, and the final determination is that vaccines are NOT the cause of autism. The relevant information is summarized in the May 2004 report of the Institute of Medicine. This final determination is especially important so that research efforts will be directed toward more likely causes of autism.

3. It was suspected that the first rotavirus vaccine, Rotashield, licensed in 1998, was associated with a rare adverse event, intussusception, where one portion of the intestine slides into another. The recommendation for Rotashield was withdrawn in July 1999, 10 months after licensure, because of concern for this very rare complication (1 in 10,000). New formulations of rotavirus vaccines were developed and tested in more than 35,000 infants and have been in use since 2006, with no increased risk of intussusception or other serious adverse events.

4. The belief that influenza vaccine causes the flu is unfounded, since the killed or injectable vaccine is incapable of replication necessary to cause infection and disease. Similarly, the live-attenuated influenza vaccine (Flu-Mist) is unlikely passed from a vaccinated person to an unvaccinated person because it is shed in quantities below the amount required for transmission to others. Furthermore, this vaccine virus cannot cause disease in the lungs because it is "cold adapted," meaning it is unable to replicate at the higher temperatures inside the lungs. It was created to specifically work and remain only inside the nose and throat.

Recommended Vaccine Schedules


Infants, Children, and Adolescents. Each year, the CDC, the AAP, and the American Academy of Family Physicians (AAFP) review the new information on vaccines from the previous year and update the recommendations for routine vaccines for children and adolescents for the upcoming year. Changes in vaccine schedules usually include addition of new vaccines that have been licensed for use and changes in numbers of doses of a specific vaccine on the basis of studies of infections that continue to occur, usually due to a waning immunity over time or inadequate primary response. The updated vaccine schedule is published in January or February each year. There are now 16 diseases that are prevented by the vaccines recommended in the schedule for children and adolescents in 2013. Information about these vaccines can be found at the following website: http://www.cdc.gov/vaccines/schedules/easy-to-read/index.html.

Adults. In 2002, the first schedule for immunizations of adults was formulated by the CDC, the AAFP, the American College of Obstetricians and Gynecologists (ACOG), and the American College of Physicians–American Society of Internal Medicine (ACP-ASIM) with the IDSA. Since that time, annual updates for the adult immunization schedule according to age and underlying condition are published at the following website: http://www.cdc.gov/vaccines/schedules/easy-to-read/index.html.

The Need for Immunizations Does Not End When You Reach Adulthood. The specific vaccines needed as an adult depend not only on age, lifestyle, overall health, pregnancy status, and travel plans but also on the risk of vaccine-preventable diseases in close contacts. It is important for adults to keep up with the vaccines recommended for them by age and underlying medical condition both for their own health and for reducing the risk of transmission of infection to vulnerable contacts. Healthcare personnel are required to receive certain vaccines according to the recommended schedule to reduce the risk of transmission of infections to vulnerable patients. Also, some vaccines are recommended for adults on the basis of age or risk for serious disease. A discussion of vaccines that are beneficial for each adult should be part of general health maintenance. More information about the recommended adult immunizations is contained in a short video available at http://www.cdc.gov/CDCTV/VSI_Vaccination/index.html.

Perspective of Family-centered Residential Facilities


Guests, such as at a RMH, are frequently (1) children with underlying medical conditions (eg, transplants, malignancy, and prematurity) that place them at increased risk for serious complications of vaccine-preventable diseases, (2) adult and child members of the families of these vulnerable children, and (3) families from foreign countries where there may still be ongoing outbreaks of vaccine-preventable diseases, such as measles. Many of the patients do not respond well to vaccines due to impairment of their immune systems, or they may be too young to receive the recommended vaccines. Therefore, it is critical to minimize their exposure to such vaccine-preventable infections by encouraging that their close contacts have received all of the recommended vaccines. Ideally, all program staff members, volunteers, and families should routinely consult with their healthcare providers to verify their immunization status and obtain the recommended vaccines. By ensuring that staff members and volunteers are up to date on recommended vaccines, the risk of exposure of vulnerable patients and their families to vaccine-preventable illnesses, such as influenza, pertussis (whooping cough), measles, mumps, and varicella (chickenpox), will be reduced. While family-centered residential facilities are not a site of healthcare delivery, the staff members and volunteers can play an important role in providing educational material to families who are far from home, stressed, and not thinking about "routine" health matters. It would be ideal for staff to provide information that reminds residents of the importance of obtaining recommended vaccines and locations where vaccines may be obtained, particularly for influenza during the winter months. This may be developed in partnership with the nearby medical facility where the majority of patients are being treated. Sick children who stay at family-centered residential facilities while receiving medical care should have their immunization records reviewed by their healthcare providers. Their ability to receive vaccines will be determined by their underlying illnesses and therapy. Some vaccines are contraindicated during specific medical therapies.

For prevention of influenza, there is strong evidence that providing vaccine to both adult and pediatric contacts of vulnerable individuals reduces the risk of the vulnerable individuals from developing influenza infection and its complications. Similar observations have been made for the pertussis vaccines, especially the adolescent and adult Tdap formulations, and for pneumococcal vaccines. Herd immunity is especially important for populations of vulnerable patients.

Specific Vaccine-related Highlights for Family-centered Residential Facility Staff


Influenza Vaccine. Influenza vaccine is now recommended annually for all individuals who are 6 months of age or older. The benefits of influenza vaccine that have been established include (1) reduced incidence of serious disease, including complications associated with influenza in recipients and in close contacts of recipients; (2) reduced absenteeism from school or work; and (3) reduced use of antimicrobial agents in patients during the flu season. Influenza vaccine does not cause the flu. Influenza vaccination is especially important for the elderly, young children between 6 months and 5 years of age, and those who have high-risk underlying medical conditions, such as pregnancy, diabetes, and neuromuscular, heart, or lung disease. It is also important to vaccinate those who have close contact (household or workplace) with vulnerable patients who are at high risk of developing severe disease and complications, may not respond well to vaccine themselves, or may be too young to receive vaccine. There are 2 types of influenza vaccines: killed vaccine (the shot) and live-attenuated vaccine (the nasal mist). Although the nasal mist may result in shedding of the weakened virus for an average of 7 days, transmission of vaccine virus occurs rarely, and serious illness associated with vaccine strain transmission has not been reported. The nasal mist vaccine may be given to otherwise healthy individuals in contact with immunosuppressed patients except for those who are in the highest-risk phase of their stem cell transplantation, when they are hospitalized in special isolation rooms. Updated information concerning influenza vaccine is published annually by the CDC.

Adult Pertussis Vaccine (Tdap). Although strides had been made in pertussis (whooping cough) control through vaccinating infants and children under 7 years of age, increasing rates of disease have been noted in the United States since 1990. Increased rates of pertussis have been attributed to waning immunity and a persistent reservoir of disease in adolescents and adults. Infants under 6 months old are too young to have received a complete pertussis vaccination series. Therefore, infants are at the highest risk of severe disease and death due to pertussis. In 2006, a new pertussis vaccine containing a lower concentration of pertussis antigens, Tdap, was licensed and is recommended as a single dose for use in adolescents 11 years of age and older. While Tdap provides a booster for protection against tetanus, the importance of Tdap for adults who are in contact with young infants must be emphasized. The most recent recommendations for Tdap vaccine are listed in Table B3.

Measles, Mumps, Rubella (German Measles), Varicella (Chickenpox). These vaccines are recommended for adults who do not have documentation of vaccination or history of disease. In addition, there is a vaccine, Zostavax, recommended for adults more than or equal to 50 years old to prevent shingles that is caused by a reactivation of the chickenpox virus. Shingles occurs in individuals who have had chickenpox in the past but have waning immunity. Protection against shingles also reduces the risk of a vulnerable patient being exposed to the varicella-zoster virus.

Hepatitis A Vaccine. Certain areas of the United States and other countries were known to have high rates of hepatitis A virus infections, often due to contaminated water supplies. However, since the introduction of hepatitis A vaccine, the rates of disease have been reduced dramatically. Hepatitis A vaccine is recommended for all children and for adults who are likely to be at risk due to travel or medical conditions, (eg, liver disease of other causes). Individuals likely to come into contact with international adoptees will also benefit from hepatitis A vaccine.

Hepatitis B Vaccine. Hepatitis B virus is transmitted through blood or body fluids and may be transmitted sexually. Occupational exposures may occur if there is contact of mucous membranes (conjunctivae, lips) or skin that is not intact with blood or body fluids of infected individuals. Individuals with diabetes are also known to have especially severe disease when they develop hepatitis B infection. Thus, hepatitis B vaccine is recommended for individuals who are sexually active, may come in contact with blood, and who have diabetes.

Pneumococcal Vaccines: The "Pneumonia" Shot, Pneumovax (PPSV 23), and Prevnar (PCV-13). The PPSV 23 vaccine is recommended for individuals over the age of 2 years who have a medical condition that places them at high risk for invasive infection due to Streptococcus pneumoniae. In addition, the vaccine is recommended for all adults over the age of 65 years because of the increased risk of more severe disease in this age group. A different form of pneumococcal vaccine (PCV-7, now PCV-13) has been given routinely to all infants since 2000. In 2012, the recommendation for PCV-13 was extended to all individuals who did not receive this vaccine during infancy and are at increased risk of developing serious disease associated with S. pneumoniae infections related to underlying medical conditions that impair their ability to fight these infections.

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