Georgia epidemiology report, Vol. 13, no. 7 (July 1997)

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

July 1997

Volume 13 Number 7
Prevention and Control of Influenza:
Recommendations of the Advisory Committee on Immunization Practices (ACIP)

http://www.ph.dhr.state.ga.us
Division Of Public Health
Patrick J. Meehan, MD - Director
Epidemiology and Prevention Branch State Epidemiologist Kathleen E Toomey, MD, MPH.- Director
Epidemiology Section Paul A Blake, MD, MPH-Chief
Notifiable Diseases
Jeffrey D Berschling, MPH; Cherie L. Drenzek, DVM, MS; Katherine Gibbs-McCombs, MPH; Karen R Horvat, MPH; Amri B Johnson, MPH; Jane E Koehler, DVM, MPH; Preeti Pathela, MPH
Chronic Disease
Nancy E Stroup, PhD-Program Manager Patricia M Fox, MPH; A Rana Bayakly, MPH; Edward E Pledger, MPA
Tuberculosis
Rose Marie Sales, MD, MPH -Program Manager Naomi Bock, MD, MS
HIV/AIDS/Sexually Transmitted Diseases
John F Beltrami, MD, MPH-Acting Program Manager Mary Lynn Gaffield, MPH.; Andrew Margolis, MPH
Perinatal Epidemiology
Mary D Brantley, MPH; Paul C Gangarosa, MPH; Raymond E Gangarosa, MD, MPH; Leslie E Lipscomb, MPH; Mary P Mathis, PhD, MPH
Preventive Medicine Resident
Scott E Kellerman, MD; Alexander K Rowe, MD
EIS Officer
Michael S Friedman, MD
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.

These recommendations update information concerning the vaccine and antiviral agents available for controlling influenza during the 199798 influenza season (superseding MMWR 1996;45[No. RR-5]:124) 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 199798, b) the vaccination of pregnant and breastfeeding women, and c) side effects and adverse reactions. For additional information about vaccine strategies and treatment, see MMWR 1997;46 [No.RR-9]:1-25.
Introduction
Influenza A viruses are classified into subtypes on the basis of two surface antigens: hemagglutinin (H) and neuraminidase (N). Three subtypes of hemagglutinin (H1, H2, and H3) and two subtypes of neuraminidase (N1 and N2) are recognized among influenza A viruses that have caused widespread human disease. Immunity to these antigens--especially to the hemagglutinin--reduces the likelihood of infection and lessens the severity of disease if infection occurs. Infection with a virus of one subtype confers little or no protection against viruses of other subtypes. Furthermore, over time, antigenic variation (antigenic drift) within a subtype may be so marked that infection or vaccination with one strain may not 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.
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 occurred among persons aged >65 years.
Options for the Control of Influenza
Two measures are available that can reduce the impact of influenza: immunoprophylaxis with inactivated (i.e., killed-virus) vaccine and chemoprophylaxis or therapy with an influenza-specific antiviral drug (amantadine or rimantadine). Vaccinating persons at high risk before the influenza season each year is the most effective measure for reducing the impact of influenza. It can be highly cost effective when it is a) directed at persons who are most likely to experience complications or who are at increased risk for exposure and b) administered to persons at high risk during hospitalizations or routine health-care visits before the influenza season, thus making special visits to physicians' offices or clinics unnecessary.
Inactivated Vaccine for Influenza A & 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. The vaccine is made from highly purified, egg-grown viruses that have been made noninfectious (inactivated). Influenza

Epidemiology Section, Epidemiology & Prevention Branch, Two Peachtree St., N.W., Atlanta, GA 30303-3186

Phone: (404) 657-2588

FAX: (404) 657-2586

vaccine rarely causes systemic or febrile reactions. Whole-virus, subvirion, and purified-surface antigen preparations are available.
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. Studies of this population have indicated that the vaccine can be 50%60% effective in preventing hospitalization and pneumonia and 80% effective in preventing death, even though efficacy in preventing influenza illness may often be in the range of 30%40% among the frail elderly. 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 aged >6 months who--because of age or underlying medical condition--is at increased risk for complications of influenza. Health-care workers and others (including household members) in close contact with persons in high-risk groups also should be vaccinated. In addition, influenza vaccine may be administered to any person who wishes to reduce the chance of becoming infected with influenza. Guidelines for the use of vaccine among certain patient populations follow; dosage recommendations vary according to age group (Table 1).
Target Groups for Special Vaccination Programs
Groups at Increased Risk for Influenza-Related Complications:
q Persons aged >65 years
q Residents of nursing homes and other chronic-care facilities that house persons of any age who have chronic medical conditions
q Adults and children who have 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 (aged 6 months18 years) who are receiving longterm aspirin therapy and therefore might be at risk for developing Reye syndrome after influenza
q Women who will be in the second or third trimester of pregnancy during the influenza season
Because the 199798 vaccine differs from the 199697 vaccine, supplies of 199697 vaccine should not be administered to provide protection for the 199798 influenza season. Two doses administered at least 1 month apart may be required for satisfactory antibody responses among previously unvaccinated children aged <9 years; 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.
During recent decades, data on influenza vaccine immunogenicity and side effects have been obtained for intramuscularly administered vaccine. Because recent influenza vaccines have not been adequately evaluated when administered by other routes, the intramuscular route is recommended. Adults and older children should be vaccinated in the deltoid muscle and infants and young children in the anterolateral aspect of the thigh.
Case reports and limited studies suggest that pregnancy may increase the risk for serious medical complications of influenza as a result of increases in heart rate, stroke volume and oxygen consumption, decreases in lung capacity, and changes in immunologic function. A recent study of the impact of influenza during 17 interpandemic influenza seasons documented that the relative risk of hospitalization for selected cardiorespiratory conditions among pregnant women increased from 1.4 during weeks 1420 of gestation to 4.7 during weeks 3742 compared with rates among women who were 16 months postpartum.
On the basis of these and other data that suggest that influenza infection

may cause increased morbidity in women during the second and third trimesters of pregnancy, the Advisory Committee on Immunization Practices (ACIP) recommends that women who will be beyond the first trimester of pregnancy (14 weeks' gestation) during the influenza season be vaccinated. 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. Studies of influenza immunization of more than 2,000 pregnant women have demonstrated no adverse fetal effects associated with influenza vaccine; however, more data are needed. Because influenza vaccine is not a live virus vaccine and major systemic reactions to it are rare, many experts consider influenza vaccination safe during any stage of pregnancy. However, because spontaneous abortion is common in the first trimester and unnecessary exposures have traditionally been avoided during this time, some experts prefer influenza vaccination during the second trimester to avoid coincidental association of the vaccine with early pregancy loss.

Table 1. Influenza Vaccine* Dosage, by Age Group -- United States, 199798 Season

Age grp Product

Dosage No. of doses Route

635 mos Split virus only

0.25 mL 1 or 2

IM**

3 8 yrs Split virus only

0.50 mL 1 or 2

IM

912 yrs Split virus only

0.50 mL 1

IM

>12 yrs

Whole / split virus 0.50 mL 1

IM

* Contains 15 mg each of A/Bayern/07/95-like (H1N1), A/Wuhan/359/ 95-like (H3N2), and B/Beijing/184/93-like hemagglutinin antigens in each 0.5 mL. For the A/Bayern/07/95-like, A/Wuhan/359/95-like, and B/Beijing/184/93-like antigens, U.S. manufacturers will use the antigenically equivalent strains A/Johannesburg/82/96(H1N1), 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. (an affiliate of Medeva Pharmaceuticals, Inc.) (FluvirinTM purified surface antigen vaccine) and Wyeth-Ayerst Laboratories (FlushieldTM split). For further product information call Connaught, (800) 822-2463; Evans/Medeva, (800) 932-1950; or Wyeth-Ayerst, (800) 358-7443.

Because of their decreased 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.

For adults and children, the recommended site of vaccination is the deltoid muscle. 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 aged <9 years who are receiving influenza vaccine for the first time.

** Intramuscular.

Groups that Can Transmit Influenza to Persons at High Risk
Persons who are clinically or subclinically infected can transmit influenza virus to persons at high risk that they care for or live with. Therefore, 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
Persons Infected with Human Immunodeficiency Virus
Influenza vaccine has produced protective antibody titers against influenza

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in vaccinated HIV-infected persons who have minimal AIDS-related symptoms and high CD4+ T-lymphocyte 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.

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 usually has consisted of local, delayed-type hypersensitivity reactions.

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.
Breastfeeding Mothers
Influenza vaccine does not affect the safety of breastfeeding for mothers or infants. Breastfeeding does not adversely affect immune response and is not a contraindication for vaccination.
Persons Traveling to Foreign Countries
The risk for exposure to influenza during travel to foreign countries 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. Because of the short incubation period for influenza, exposure to the virus during travel can result in clinical illness that begins while traveling, which is an inconvenience or potential danger, especially for persons at increased risk for complications. 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 highrisk groups 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.
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 (e.g., those who reside in dormitories) should be encouraged to receive vaccine to minimize the disruption of routine activities during epidemics.
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 (see Side Effects and Adverse Reactions). Use of an antiviral agent (i.e., amantadine or rimantadine) is an option for prevention of influenza A in such persons. 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.

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 in subsequent years, the estimated risk for GBS was much lower than 1:100,000 and substantially less than that for severe influenza, which could be prevented by vaccination, especially for persons aged >65 years and those who have medical indications for influenza vaccination.
Persons with a history of GBS have a greater likelihood of subsequently developing GBS than persons without such a history. Although avoiding a subsequent influenza vaccination in persons known to have developed GBS within 6 weeks of a previous influenza vaccination seems prudent, 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 vaccination.
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, health-care providers should strongly consider administering pneumococcal and influenza vaccines concurrently. Both vaccines can be administered at the same time at different sites without increasing side effects. However, influenza vaccine is administered each year, whereas pneumococcal vaccine is not. Children at high risk for influenza-related complications can receive influenza vaccine at the same time they receive other routine vaccinations, including pertussis vaccine (DTaP or DTP). Because influenza vaccine can cause fever when administered to young children, DTaP (which is less frequently associated with fever and other adverse events) is preferable.
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. Opportunities to vaccinate persons at high risk for complications of influenza should not be missed.
The optimal time for organized vaccination campaigns for persons in highrisk groups is usually the period from October through mid-November. 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.

Side Effects and Adverse Reactions
The most frequent side effect of vaccination is soreness at the vaccination site that lasts up to 2 days. These local reactions generally are mild and rarely interfere with the ability to conduct usual daily activities. In addition, two types of systemic reactions have occurred:
q Fever, malaise, myalgia, and other systemic symptoms can occur following vaccination 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) rarely occur after influenza vaccination. These reactions probably result from hypersensitivity to some vaccine component; most reactions likely are caused by residual egg protein. 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

Children aged <9 years 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.
Sources of Information on Influenza-Control Programs
Information regarding influenza surveillance is available through the CDC Voice Information System (influenza update), telephone (404) 332-4551, or through the CDC Information Service on the Public Health Network electronic bulletin board. From October through May, the information is updated at least every other week. In addition, periodic updates about influenza are published in the weekly MMWR. State and local health departments should be consulted regarding availability of influenza vaccine, access to vaccination programs, and information about state or local influenza activity.
For more information from the Georgia Immunizations Program call (404) 657-3158.

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The Georgia Epidemiology Report Epidemiology and Prevention Branch Two Peachtree St., NW Atlanta, GA 30303-3186

July 1997

Volume 13 Number 7

Reported Cases of Selected Notifiable Diseases in Georgia Profile* for April 1997

Selected Notifiable Diseases Campylobacteriosis

Total Reported for April 1997 24

Previous 3 Months Total

Ending in April

1995

1996

1997

200

152

102

Previous 12 Months Total

Ending in April

1995

1996

1997

838

978

726

Chlamydia genital infection Cryptosporidiosis

1475 0

2735 0

3300 13

3982 6

3431 0

12200 17

14208 84

E. coli O157:H7

4

1

6

8

4

34

50

Giardiasis Gonorrhea Haemophilis influenzae (invasive)

36 1636
0

128 4759
20

149 4828
15

176 4627
11

334 6717
31

616 21421
35

874 19271
47

Hepatitis A (acute)

49

38

88

126

54

138

466

Hepatitis B (acute)

25

Blood Lead Level > 10 g/dL (cap)

212

Blood Lead Level > 10 g/dL (ven)

75

Legionellosis

0

Lyme Disease

0

Meningococcal Disease (invasive)

14

53

6

43

639

644

590

120

130

204

6

2

0

6

0

0

28

52

37

91

44

103

785

3003

2951

158

628

736

15

10

1

8

8

2

60

133

124

Mumps

3

4

1

3

4

9

12

Pertussis Rubella

16

7

7

16

31

35

0

0

0

0

0

0

0

Salmonellosis

73

187

203

219

1137

1703

1459

Shigellosis Syphilis - Primary Syphilis - Secondary

52

379

147

224

1669

1028

1230

11

61

54

39

199

284

179

35

154

141

101

499

637

449

Syphilis - Early Latent

113

488

339

324

1624

1538

1282

Syphilis - Other** Syphilis - Congenital

122

267

249

358

786

1149

1106

2

11

14

10

37

63

28

Tuberculosis

67

170

203

194

616

801

766

* 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.

** Other syphilis includes latent (unknown duration), late latent, late with symptomatic manifestations, and neurosyphilis.

Report Period

Total Cases Reported *

AIDS Profile Update

Percent

Risk Group Distribution (%)

Race Distribution (%)

Female

MSM IDU MSM&IDU HS Blood Unknown White Black Other

Last 12 Mos 07/96 to 06/97 5 Yrs Ago 07/91 to 06/92 Cumulative 01/80 to 06/97

2133 1987 17960

21.7

38.5 17.6

4.6

14.2

51.3 23.3

7.7

14.8

51.2 18.9

5.9

16.6 1.4

20.9

9.9 1.9

4.9

11.2 1.8

9.9

27.7 69.7 2.6 38.9 59.2 1.9 40.1 57.9 2.0

MSM - Men having sex with men IDU - Injection drug users HS - Heterosexual * Case totals are accumulated by date of report to the Epidemiology Section

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