Influenza Vaccination in Pregnancy
Purpose: The Centers for Disease Control (CDC) identify women in their second and third trimesters as a high-risk population warranting influenza vaccination. This study attempted to characterize understanding of these guidelines and obstacles to their implementation in a suburban community.
Methods: Family physicians and obstetricians with admitting privileges to a community-based hospital were surveyed regarding estimated vaccine availability and administration in their practices and regarding knowledge of indications and contraindications to influenza vaccination in pregnancy.
Results: Of the 20 obstetricians and 66 family physicians completing the survey, 68.4% of obstetricians and 90.5% of family physicians carried the vaccine in their offices (P = .027). Both obstetricians and family physicians incorrectly perceived multiple factors as contraindications to influenza vaccination in pregnancy. Obstetricians and family physicians reported similar proportions of their pregnant patients received the vaccine (35 versus 40%).
Conclusions: In this study, more family physicians had the influenza vaccine available than obstetricians, but there was no difference in estimated rates of vaccination during pregnancy or in the understanding of its indications and contraindications. Finally, no physicians in our community reported providing influenza vaccination in pregnancy at recommended frequencies. Further research is needed to clarify methods of improving vaccination rates in both family practice and obstetric settings.
Every year, the influenza virus affects 10% to 20% of the US population, with hundreds of thousands of patients hospitalized because of influenza infection and complications. Each epidemic results in more than 100,000 hospitalizations and more than 20,000 deaths. The influenza virus constantly undergoes genetic recombination of the coding for surface antigens. Point mutations result in minor structural changes (antigenic drift) of these proteins, whereas genetic recombination resulting in more major alterations in surface antigens (antigenic shift) clinically accounts for major periodic epidemics of disease. Both frustrate the development of immunity on an individual or global scale.
Aerosolized respiratory secretions transmit the influenza virus. These secretions attach to respiratory epithelium and are shed for 5 to 10 days after an incubation period of 1 to 5 days. Confounding efforts to contain the disease, the period of maximal communicability may start 1 to 2 days before symptom onset. Classic symptoms of fever, myalgia, cough, and headache are seen in only about 50% of infections, depending on prior immunologic exposure to antigenically similar viruses and other aspects of the host's general condition. Although the duration of illness generally does not exceed 3 to 5 days, some may experience prolonged symptoms of cough, malaise, and fatigue for weeks.
In addition to being a frequent cause of morbidity, influenza infection often contributes to mortality from associated complications. The elderly and those with pre-existing pulmonary disease are particularly susceptible to secondary bacterial pneumonia. Influenza infection also often exacerbates long-term health problems, carrying significant morbidity and mortality implications as well. Although less common, primary influenza pneumonia carries a high case-fatality rate. Other conditions, such as Reye syndrome and myocarditis, are much more rare.
Because numerous problems surround efforts to stop the spread of the virus through isolation or treatment of infected persons, most prevention efforts focus on immunization of at-risk populations. Because of antigenic drift of the influenza virus, the vaccine is reformulated annually to contain inactivated antigens of the strains deemed most likely to cause infection in the coming year. Although efficacy of the vaccine varies widely with host and environmental factors, it is up to 90% effective in preventing disease among healthy, immunocompetent adults. Even among the elderly, it is approximately 60% effective in preventing hospitalizations. Adverse reactions are mild, with 10% to 64% experiencing limited local reactions (soreness or redness) but other symptoms (including fever, myalgia, headache, or fatigue) occurring no more often than with placebo.
Whereas 40% to 50% of hospitalizations and 90% of deaths occur in patients over 65 years old, studies have also demonstrated increased risk of complications in younger patients residing in long-term care facilities; those with chronic diseases, such as asthma; and pregnant women. Efficacy is maximized if the vaccine is administered 2 weeks before exposure to the virus. The Centers for Disease Control (CDC) identified at-risk populations for the 2003 to 2004 influenza season ( Table 1 ), eliminating the previously accepted tiered fashion of vaccination prioritization.
Women in their second and third trimesters of pregnancy have an increased risk of influenza-related complications including pneumonia and a 4-fold risk of hospitalization. Because these hospitalization rates are comparable with those of non-pregnant women with high-risk medical conditions, the CDC has adopted similar guidelines regarding vaccination for both groups. Women who will be in the second or third trimester during influenza season and all pregnant women with additional high-risk medical conditions should receive vaccination in the fall. Some advocate avoidance of vaccination during the first trimester and instead vaccinate during preconception planning or after 14 weeks' gestation. The first trimester poses no significant increase from baseline in the risk of influenza-related complications, and routine administration of any vaccine during this time may prompt anecdotal association with naturally occurring spontaneous miscarriage. Adverse effects from influenza vaccination are uncommon. Localized soreness is frequently noted; infrequent mild symptoms, such as fever, malaise, and myalgias, are reported with frequency similar to that of placebo injection. These symptoms usually occur after the initial vaccination and last only 1 to 2 days. Breast-feeding is not a contraindication to vaccination.
Despite publication of these guidelines, rates of vaccination among high-risk patients remain low. Many possible explanations exist for this discrepancy, including vaccine unavailability, logistic concerns, poor reimbursement, fear of side effects, and lack of adequate patient or physician education. This survey tool was designed to assess physicians' individual practice styles and awareness of CDC recommendations for influenza vaccination during pregnancy. It is our hope that by characterizing the understanding and application of current knowledge to patient care, obstacles can be identified, and more effective interventions can be designed to increase rates of vaccination among pregnant women in the community.
Purpose: The Centers for Disease Control (CDC) identify women in their second and third trimesters as a high-risk population warranting influenza vaccination. This study attempted to characterize understanding of these guidelines and obstacles to their implementation in a suburban community.
Methods: Family physicians and obstetricians with admitting privileges to a community-based hospital were surveyed regarding estimated vaccine availability and administration in their practices and regarding knowledge of indications and contraindications to influenza vaccination in pregnancy.
Results: Of the 20 obstetricians and 66 family physicians completing the survey, 68.4% of obstetricians and 90.5% of family physicians carried the vaccine in their offices (P = .027). Both obstetricians and family physicians incorrectly perceived multiple factors as contraindications to influenza vaccination in pregnancy. Obstetricians and family physicians reported similar proportions of their pregnant patients received the vaccine (35 versus 40%).
Conclusions: In this study, more family physicians had the influenza vaccine available than obstetricians, but there was no difference in estimated rates of vaccination during pregnancy or in the understanding of its indications and contraindications. Finally, no physicians in our community reported providing influenza vaccination in pregnancy at recommended frequencies. Further research is needed to clarify methods of improving vaccination rates in both family practice and obstetric settings.
Every year, the influenza virus affects 10% to 20% of the US population, with hundreds of thousands of patients hospitalized because of influenza infection and complications. Each epidemic results in more than 100,000 hospitalizations and more than 20,000 deaths. The influenza virus constantly undergoes genetic recombination of the coding for surface antigens. Point mutations result in minor structural changes (antigenic drift) of these proteins, whereas genetic recombination resulting in more major alterations in surface antigens (antigenic shift) clinically accounts for major periodic epidemics of disease. Both frustrate the development of immunity on an individual or global scale.
Aerosolized respiratory secretions transmit the influenza virus. These secretions attach to respiratory epithelium and are shed for 5 to 10 days after an incubation period of 1 to 5 days. Confounding efforts to contain the disease, the period of maximal communicability may start 1 to 2 days before symptom onset. Classic symptoms of fever, myalgia, cough, and headache are seen in only about 50% of infections, depending on prior immunologic exposure to antigenically similar viruses and other aspects of the host's general condition. Although the duration of illness generally does not exceed 3 to 5 days, some may experience prolonged symptoms of cough, malaise, and fatigue for weeks.
In addition to being a frequent cause of morbidity, influenza infection often contributes to mortality from associated complications. The elderly and those with pre-existing pulmonary disease are particularly susceptible to secondary bacterial pneumonia. Influenza infection also often exacerbates long-term health problems, carrying significant morbidity and mortality implications as well. Although less common, primary influenza pneumonia carries a high case-fatality rate. Other conditions, such as Reye syndrome and myocarditis, are much more rare.
Because numerous problems surround efforts to stop the spread of the virus through isolation or treatment of infected persons, most prevention efforts focus on immunization of at-risk populations. Because of antigenic drift of the influenza virus, the vaccine is reformulated annually to contain inactivated antigens of the strains deemed most likely to cause infection in the coming year. Although efficacy of the vaccine varies widely with host and environmental factors, it is up to 90% effective in preventing disease among healthy, immunocompetent adults. Even among the elderly, it is approximately 60% effective in preventing hospitalizations. Adverse reactions are mild, with 10% to 64% experiencing limited local reactions (soreness or redness) but other symptoms (including fever, myalgia, headache, or fatigue) occurring no more often than with placebo.
Whereas 40% to 50% of hospitalizations and 90% of deaths occur in patients over 65 years old, studies have also demonstrated increased risk of complications in younger patients residing in long-term care facilities; those with chronic diseases, such as asthma; and pregnant women. Efficacy is maximized if the vaccine is administered 2 weeks before exposure to the virus. The Centers for Disease Control (CDC) identified at-risk populations for the 2003 to 2004 influenza season ( Table 1 ), eliminating the previously accepted tiered fashion of vaccination prioritization.
Women in their second and third trimesters of pregnancy have an increased risk of influenza-related complications including pneumonia and a 4-fold risk of hospitalization. Because these hospitalization rates are comparable with those of non-pregnant women with high-risk medical conditions, the CDC has adopted similar guidelines regarding vaccination for both groups. Women who will be in the second or third trimester during influenza season and all pregnant women with additional high-risk medical conditions should receive vaccination in the fall. Some advocate avoidance of vaccination during the first trimester and instead vaccinate during preconception planning or after 14 weeks' gestation. The first trimester poses no significant increase from baseline in the risk of influenza-related complications, and routine administration of any vaccine during this time may prompt anecdotal association with naturally occurring spontaneous miscarriage. Adverse effects from influenza vaccination are uncommon. Localized soreness is frequently noted; infrequent mild symptoms, such as fever, malaise, and myalgias, are reported with frequency similar to that of placebo injection. These symptoms usually occur after the initial vaccination and last only 1 to 2 days. Breast-feeding is not a contraindication to vaccination.
Despite publication of these guidelines, rates of vaccination among high-risk patients remain low. Many possible explanations exist for this discrepancy, including vaccine unavailability, logistic concerns, poor reimbursement, fear of side effects, and lack of adequate patient or physician education. This survey tool was designed to assess physicians' individual practice styles and awareness of CDC recommendations for influenza vaccination during pregnancy. It is our hope that by characterizing the understanding and application of current knowledge to patient care, obstacles can be identified, and more effective interventions can be designed to increase rates of vaccination among pregnant women in the community.
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