Georgia Epidemiology Report The Georgia Epidemiology Report is a publication of the Epidemiology Section of the Epidemiology and Prevention Branch, Division of Public Health, Department of Human Resources August 1996 Volume 12 Number 8 Prevention & Control of Influenza: Vaccines Recommendations of the Advisory Committee on Immunization Practices (ACIP) http://www.ph.dhr.state.ga.us Division Of Public Health Patrick J. Meehan, M.D. - Director Epidemiology and Prevention Branch State Epidemiologist Kathleen E. Toomey, M.D., M.P.H.- Director Epidemiology Section Paul A. Blake, M.D., M.P.H.-Chief Notifiable Diseases Jeffrey D. Berschling, M.P.H.; Karen R. Horvat, M.P.H.; Jane E. Koehler, D.V.M, M.P.H.; Preeti Pathela, M.P.H.; Sabrina Walton, M.S.P.H. Chronic Disease Nancy E. Stroup, Ph.D.-Program Manager Patricia M. Fox, M.P.H.; David M. Homa, Ph.D., M.P.H.; Thomas W. McKinley, M.P.H.; Edward E. Pledger, M.P.A.; D. Lee Warner, M.P.H. Tuberculosis Naomi Bock, M.D., M.S. HIV/AIDS/Sexually Transmitted Diseases Kim Cook, M.D., M.S.P.H.-Program Manager Awal D. Khan, Ph.D., M.A.; Stephanie Bock, M.P.H.; Andrew Margolis, M.P.H. Office of Perinatal Epidemiology Roger W. Rochat, M.D. - Program Manager Mary D. Brantley, M.P.H.; Raymond E. Gangarosa, M.D., M.P.H.; Rebekah Hudgins, M.P.H.; Mary P. Mathis, Ph.D., M.P.H.; Florina Serbanescu, M.D.; Edward F. Tierney, M.P.H. Preventive Medicine Residents Hussain R. Yusuf, M.B.B.S., M.P.H.; E. Anne Peterson, M.D. EIS Officer Michael S. Friedman, M.D. Georgia Epidemiology Report Editorial Board Editorial Executive Committee Paul A. Blake, M.D., M.P.H.- Editor Kathleen E. Toomey, M.D., M.P.H. Mary D. Brantley, M.P.H. Jeffrey D. Berschling, M.P.H. Mailing List Edward E. Pledger, M.P.A. This issue is an abridged version of MMWR 1996;45 (no.RR-5). These recommendations update information on vaccines available for controlling influenza during the 199697 influenza season (superseding MMWR 1995;44(No. RR-3):122) and the Georgia Epidemiology Report Vol 11 No. 8. The principal changes include information about a) the influenza virus strains included in the trivalent vaccine for 199697 and b) extension of the optimal time for influenza vaccination campaigns for persons in high-risk groups. For additional information about vaccine strategies and treatment, see the MMWR. INTRODUCTION Influenza A viruses are classified into subtypes on the basis of two surface antigens: hemagglutinin (H) and neuraminidase (N). Infection with a virus of one subtype confers little or no protection against viruses of other subtypes. Antigenic variation (antigenic drift) over time within a subtype may be so marked that infection or vaccination with one strain may not continue to induce immunity to distantly related strains of the same subtype. For these reasons, major epidemics of respiratory disease caused by new variants of influenza continue to occur. The antigenic characteristics of circulating strains provide the basis for selecting the virus strains included in each year's vaccine. Typical influenza illness is characterized by abrupt onset of fever, myalgia, sore throat, and nonproductive cough. Unlike other common respiratory illnesses, influenza can cause severe malaise lasting several days. More severe illness can result if either primary influenza pneumonia or secondary bacterial pneumonia occurs. During influenza epidemics, high attack rates of acute illness result in both increased numbers of visits to physicians' offices, walk-in clinics, and emergency rooms and increased hospitalizations for management of lower respiratory tract complications. Elderly persons and persons with underlying health problems are at increased risk for complications of influenza and are more likely than the general population to require hospitalization. During major epidemics, hospitalization rates for persons at high risk may increase twofold to fivefold, depending on the age group. Increased mortality in influenza epidemics results not only from influenza and pneumonia but also from cardiopulmonary and other chronic diseases that can be exacerbated by influenza. More than 90% of the deaths attributed to pneumonia and influenza occur among persons >65 years of age. Because the proportion of elderly persons in the U.S. population is increasing and because age and its associated chronic diseases are risk factors for severe influenza illness, the number of deaths from influenza can be expected to increase unless control measures are implemented vigorously. The number of persons <65 years of age at increased risk for influenza-related complications is also increasing. Better survival rates for organ-transplant recipients, the success of neonatal intensive-care units, and better management of diseases such as cystic fibrosis and acquired immunodeficiency syndrome (AIDS) result in a higher survival rate for younger persons at high risk. Errata--"Genital Ulcer Disease in Fulton County", Georgia Epidemiology Report, Vol 12:No 7 (July 1996), page 2, col 2, para 4. The corrected treatment for syphilis is Benzathine penicillin G, 2.4 million units IM in a single dose. Epidemiology Section, Epidemiology & Prevention Branch, Two Peachtree St., N.W., Atlanta, GA 30303-3186 Phone: (404) 657-2588 FAX: (404) 657-2586 INACTIVATED VACCINE FOR INFLUENZA A AND B Each year's influenza vaccine contains three virus strains (usually two type A and one type B) representing the influenza viruses that are likely to circulate in the United States in the upcoming winter. Whole-virus, subvirion, and purified-surface antigen preparations are available. To minimize febrile reactions, only subvirion or purified-surfaceantigen preparations should be used for children; any of the preparations may be used for adults. Most vaccinated children and young adults develop high postvaccination hemagglutination-inhibition antibody titers. Elderly persons and persons with certain chronic diseases may develop lower postvaccination antibody titers than healthy young adults and thus may remain susceptible to influenza-related upper respiratory tract infection. However, even if such persons develop influenza illness despite vaccination, the vaccine can be effective in preventing lower respiratory tract involvement or other secondary complications, thereby reducing the risk for hospitalization and death. The effectiveness of influenza vaccine in preventing or attenuating illness varies, depending primarily on the age and immunocompetence of the vaccine recipient and the degree of similarity between the virus strains included in the vaccine and those that circulate during the influenza season. Among elderly persons residing in nursing homes, influenza vaccine is most effective in preventing severe illness, secondary complications, and death. Achieving a high rate of vaccination among nursing home residents can reduce the spread of infection in a facility, thus preventing disease through herd immunity. RECOMMENDATIONS FOR THE USE OF INFLUENZA VACCINE Influenza vaccine is strongly recommended for any person >6 months of age who--because of age or underlying medical condition--is at increased risk for complications of influenza. Healthcare workers and others (including household members) in close contact with persons in high-risk groups should also be vaccinated. The trivalent influenza vaccine prepared for the 199697 season will include A/Texas/36/91-like (H1N1), A/Wuhan/359/95-like (H3N2), and B/Beijing/184/93-like hemagglutinin antigens. Guidelines for the use of vaccine among certain patient populations follow; dosage recommendations are also summarized (Table 1). TABLE 1. Influenza vaccine* dosage, by age group -- United States, 199697 season Age group 635 mos 3 8 yrs 912 yrs >12 yrs Product Split virus only Split virus only Split virus only Whole or split virus Dosage 0.25 mL 0.50 mL 0.50 mL 0.50 mL No. of doses 1 or 2 1 or 2 1 1 Route IM IM IM IM * Contains 15 mg each of A/Texas/36/91-like (H1N1), A/Wuhan/359/95-like (H3N2), and B/Beijing/184/93-like hemagglutinin antigens in each 0.5 mL. For both A/Wuhan/359/95-like and B/Beijing/184/93-like antigens, U.S. manufacturers will use the antigenically equivalent strains A/Nanchang/933/95 (H3N2) and B/Harbin/07/94 because of their growth properties. Manufacturers include: Connaught Laboratories, Inc. (Fluzone whole or split); Evans Medical Ltd. (distributed by Adams Laboratories, Inc.) (FluvirinTM purified surface antigen vaccine); Parke-Davis (Fluogen split); and Wyeth- Ayerst Laboratories (FlushieldTM split). For further product information call Connaught, (800) 8222463; Adams, (800) 932-1950; Parke-Davis, (800) 223-0432; Wyeth-Ayerst, (800) FLU-SHIELD. Because of the lower potential for causing febrile reactions, only split-virus vaccines should be used for children. They may be labeled as "split," "subvirion," or "purified-surface-antigen" vaccine. Immunogenicity and side effects of split- and whole-virus vaccines are similar among adults when vaccines are administered at the recommended dosage. The recommended site of vaccination is the deltoid muscle for adults and older children. The preferred site for infants and young children is the anterolateral aspect of the thigh. Two doses administered at least 1 month apart are recommended for children <9 years of age who are receiving influenza vaccine for the first time. The current influenza vaccine can contain one or more of the antigens administered in previous years, however annual vaccination with the current vaccine is necessary because immunity declines in the year following vaccination. Because the 199697 vaccine differs from the 199596 vaccine, supplies of 199596 vaccine should not be administered to provide protection for the 199697 influenza season. Two doses administered at least 1 month apart may be required for satisfactory antibody responses among previously unvaccinated children <9 years of age; however, studies of vaccines similar to those being used currently have indicated little or no improvement in antibody response when a second dose is administered to adults during the same season. Adults and older children should be vaccinated in the deltoid muscle and infants and young children in the anterolateral aspect of the thigh. TARGET GROUPS FOR SPECIAL VACCINATION PROGRAMS To maximize protection of high-risk persons, they and their close contacts should be targeted for organized vaccination programs. Groups at Increased Risk for Influenza-Related Complications: q Persons >65 years of age q Residents of nursing homes and other chronic-care facilities that house persons of any age with chronic medical conditions q Adults and children with chronic disorders of the pulmonary or cardiovascular systems, including children with asthma q Adults and children who have required regular medical follow-up or hospitalization during the preceding year because of chronic metabolic diseases (including diabetes mellitus), renal dysfunction, hemoglobinopathies, or immunosuppression (including immunosuppression caused by medications) q Children and teenagers (6 months18 years of age) who are receiving longterm aspirin therapy and therefore might be at risk for developing Reye syndrome after influenza Groups that Can Transmit Influenza to Persons at High Risk Persons who are clinically or subclinically infected and who care for or live with members of high-risk groups can transmit influenza virus to them. The following groups should be vaccinated: q physicians, nurses, and other personnel in both hospital and outpatient-care settings; q employees of nursing homes and chronic-care facilities who have contact with patients or residents; q providers of home care to persons at high risk (e.g., visiting nurses and volunteer workers); and q household members (including children) of persons in high-risk groups. VACCINATION OF OTHER GROUPS General Population Physicians should administer influenza vaccine to any person who wishes to reduce the likelihood of becoming ill with influenza. Persons who provide essential community services should be considered for vaccination to minimize disruption of essential activities during influenza outbreaks. Students or other persons in institutional settings should be encouraged to receive vaccine to minimize the disruption of routine activities during epidemics. Pregnant Women Case reports and limited studies suggest that women in the third trimester of pregnancy and early puerperium, including those women without underlying risk factors, might be at increased risk for serious complications following influenza infection. Certain pregnancy-related physiologic changes may increase the risk for such complications; as pregnancy progresses, cardiac output, heart rate, oxygen consumption, and stroke volume increase while lung capacity decreases. Immunologic changes during pregnancy also may increase the risk for severe influenza illness. Healthcare workers who provide care for pregnant women should consider administering influenza vaccine to all women who would be in the third trimester of pregnancy or early puerperium during the influenza season. Pregnant women who have medical conditions that increase their risk for complications from influenza should be vaccinated before the influenza season, regardless of the stage of pregnancy. Although definitive studies have not been conducted, influenza vaccination is considered safe at any stage of pregnancy. - 2 - Persons Infected with Human Immunodeficiency Virus (HIV) Limited information exists regarding the frequency and severity of influenza illness among HIV-infected persons, but reports suggest that symptoms might be prolonged and the risk for complications increased for some HIV-infected persons. Influenza vaccine has produced protective antibody titers against influenza in vaccinated HIV-infected persons who have minimal AIDS-related symptoms and high CD4+ Tlymphocyte cell counts. In patients who have advanced HIV disease and low CD4+ T-lymphocyte cell counts, however, influenza vaccine may not induce protective antibody titers; a second dose of vaccine does not improve the immune response for these persons. Deterioration of CD4+ T-lymphocyte cell counts and progression of clinical HIV disease have not been demonstrated among HIV-infected persons who receive vaccine. Because influenza can result in serious illness and complications and because influenza vaccination may result in protective antibody titers, vaccination will benefit many HIV-infected patients. Foreign Travelers The risk for exposure to influenza during foreign travel varies, depending on season and destination. In the tropics, influenza can occur throughout the year; in the Southern Hemisphere, most activity occurs from April through September. Persons preparing to travel to the tropics at any time of year or to the Southern Hemisphere from April through September should review their influenza vaccination histories. If they were not vaccinated the previous fall or winter, they should consider influenza vaccination before travel. Persons in high-risk categories should be especially encouraged to receive the most current vaccine. Persons at high risk who received the previous season's vaccine before travel should be revaccinated in the fall or winter with the current vaccine. propriate evaluation to help determine if vaccine should be administered. Persons with documented immunoglobulin E (IgE)-mediated hypersensitivity to eggs--including those who have had occupational asthma or other allergic responses due to exposure to egg protein--might also be at increased risk for reactions from influenza vaccine, and similar consultation should be considered. The protocol for influenza vaccination developed by Murphy and Strunk may be considered for patients who have egg allergies and medical conditions that place them at increased risk for influenza-associated complications. Hypersensitivity reactions to any vaccine component can occur. Although exposure to vaccines containing thimerosal can lead to induction of hypersensitivity, most patients do not develop reactions to thimerosal when administered as a component of vaccines--even when patch or intradermal tests for thimerosal indicate hypersensitivity. When reported, hypersensitivity to thimerosal has usually consisted of local, delayed-type hypersensitivity reactions. Unlike the 1976 swine influenza vaccine, subsequent vaccines prepared from other virus strains have not been clearly associated with an increased frequency of Guillain-Barr syndrome (GBS). Even if GBS were a true side effect, the very low estimated risk for GBS is less than that for severe influenza that could be prevented by vaccination. Whereas the incidence of GBS in the general population is very low, persons with a history of GBS have a substantially greater likelihood of subsequently developing GBS than persons without such a history. Although it would seem prudent to avoid a subsequent influenza vaccination in a person known to have developed GBS within 6 weeks of a previous influenza vaccination, for most persons with a history of GBS who are at high risk for severe complications from influenza, the established benefits of influenza vaccination justify yearly immunization. PERSONS WHO SHOULD NOT BE VACCINATED Inactivated influenza vaccine should not be administered to persons known to have anaphylactic hypersensitivity to eggs or to other components of the influenza vaccine without first consulting a physician. Use of an antiviral agent (i.e., amantadine or rimantadine) is an option for prevention of influenza A in such persons. However, persons who have a history of anaphylactic hypersensitivity to vaccine components but who are also at high risk for complications of influenza can benefit from vaccine after appropriate allergy evaluation and desensitization. Specific information about vaccine components can be found in package inserts for each manufacturer. Adults with acute febrile illness usually should not be vaccinated until their symptoms have abated. However, minor illnesses with or without fever should not contraindicate the use of influenza vaccine, particularly among children with mild upper respiratory tract infection or allergic rhinitis. SIDE EFFECTS AND ADVERSE REACTIONS Because influenza vaccine contains only noninfectious viruses, it cannot cause influenza. Respiratory disease after vaccination represents coincidental illness unrelated to influenza vaccination. The most frequent side effect of vaccination reported by fewer than one third of vaccinees is soreness at the vaccination site that lasts for up to 2 days. In addition, two types of systemic reactions have occurred: q Fever, malaise, myalgia, and other systemic symptoms occur infrequently and most often affect persons who have had no exposure to the influenza virus antigens in the vaccine (e.g., young children). These reactions begin 612 hours after vaccination and can persist for 1 or 2 days; q Immediate--presumably allergic--reactions (e.g., hives, angioedema, allergic asthma, and systemic anaphylaxis) occur rarely after influenza vaccination. These reactions probably result from hypersensitivity to some vaccine component; the majority of reactions are most likely related to residual egg protein. Although current influenza vaccines contain only a small quantity of egg protein, this protein can induce immediate hypersensitivity reactions among persons who have severe egg allergy. Persons who have developed hives, have had swelling of the lips or tongue, or have experienced acute respiratory distress or collapse after eating eggs should consult a physician for ap- SIMULTANEOUS ADMINISTRATION OF OTHER VACCINES, INCLUDING CHILDHOOD VACCINES The target groups for influenza and pneumococcal vaccination overlap considerably. For persons at high risk who have not previously been vaccinated with pneumococcal vaccine, healthcare providers should strongly consider administering both pneumococcal and influenza vaccines concurrently. Both vaccines can be administered at the same time at different sites without increasing side effects. Children at high risk for influenza-related complications can receive influenza vaccine at the same time they receive other routine vaccinations, including pertussis vaccine (DTP or DTaP). Because influenza vaccine can cause fever when administered to young children, DTaP might be preferable in those children >15 months of age who are receiving the fourth or fifth dose of pertussis vaccine. DTaP is not licensed for the initial threedose series of pertussis vaccine. TIMING OF INFLUENZA VACCINATION ACTIVITIES Beginning each September (when vaccine for the upcoming influenza season becomes available) persons at high risk who are seen by health-care providers for routine care or as a result of hospitalization should be offered influenza vaccine. In previously published recommendations, the optimal time for organized vaccination campaigns for persons in high-risk groups was defined as the period from mid-October through mid-November. This period has been extended to include the first 2 weeks in October. In the United States, influenza activity generally peaks between late December and early March. High levels of influenza activity infrequently occur in the contiguous 48 states before December. Administering vaccine too far in advance of the influenza season should be avoided in facilities such as nursing homes, because antibody levels might begin to decline within a few months of vaccination. Vaccination programs can be undertaken as soon as current vaccine is available if regional influenza activity is expected to begin earlier than December. Children <9 years of age who have not been vaccinated previously should receive two doses of vaccine at least 1 month apart to maximize the likelihood of a satisfactory antibody response to all three vaccine antigens. The second dose should be administered before December, if possible. Vaccine should be offered to both children and adults up to and even after influenza virus activity is documented in a community. - 3 - The Georgia Epidemiology Report Epidemiology and Prevention Branch Two Peachtree St., NW Atlanta, GA 30303-3186 August 1996 Volume 12 Number 8 Reported Cases of Selected Notifiable Diseases in Georgia Profile for May 1996 Selected Notifiable Diseases Campylobacteriosis Giardiasis H. influenzae Meningococcal Disease Rubella Salmonellosis Shigellosis Viral Meningitis Tuberculosis Congenital Syphilis Early Syphilis Other Syphilis Cryptosporidiosis E. coli O157:H7 Legionnaires' Disease Lyme Disease Mumps Pertussis Total Reported for May 1996 61 43 9 13 0 89 36 4 63 11 149 77 3 3 1 1 0 4 Previous 3 Months Total Ending in May 1996 1995 1994 165 247 215 147 120 138 31 24 21 53 28 33 0 0 0 207 245 278 128 407 375 10 11 18 205 183 200 16 12 14 512 648 713 248 261 234 13 6 3 8 1 2 3 6 50 1 9 39 1 2 4 10 4 4 Previous 12 Months Total Ending in May 1996 1995 1994 928 1146 694 620 455 405 104 61 72 154 89 92 0 7 0 1660 1547 1331 903 2054 758 100 72 146 797 746 787 69 50 74 2384 2544 3313 1098 896 916 120 26 11 37 26 17 8 56 91 6 77 83 9 13 14 35 33 50 The cumulative numbers in the above table reflect the date the disease was first diagnosed rather than the date the report was received at the state office; and therefore are subject to change over time due to late reporting. The 3 month delay in the disease profile for a given month is designed to minimize any changes that may occur. This method of summarizing data is expected to provide a better overall measure of disease trends and patterns in Georgia. Report Period Total Cases Reported * Percent Female AIDS Profile Update MSM Risk Group Distribution (%) IDU MSM&IDU HS Blood Unknown Race Distribution (%) White Black Other Last 12 Mos 08/95 to 07/96 5 Yrs Ago 08/90 to 07/91 Cumulative 01/80 to 07/96 2322 1376 15962 17.1 11.3 13.8 46.4 17.6 4.1 61.2 18.2 5.5 52.9 19.1 6.0 15.4 1.3 15.2 35.7 61.2 3.2 8.6 2.0 4.5 47.7 51.1 1.1 10.4 2.1 9.5 41.6 56.4 2.0 MSM - Men having sex with men IDU - Injection drug users * Case totals are accumulated by date of report to the Epidemiology Section HS - Heterosexual - 4-