Georgia epidemiology report, Vol. 16, no. 11 (Nov. 2000)

November 2000

volume 16 number 11

Division of Public Health http://health.state.ga.us
Kathleen E. Toomey, M.D., M.P.H. Director
State Health Officer
Epidemiology Branch http://health.state.ga.us/epi
Paul A. Blake, M.D., M.P.H. Director
State Epidemiologist
Mel Ralston Public Health Advisor
Georgia Epidemiology Report Editorial Board
Carol A. Hoban, M.S., M.P.H. - Editor Kathryn E. Arnold, M.D. Paul A. Blake, M.D., M.P.H.
Susan Lance-Parker, D.V.M., Ph.D. Kathleen E. Toomey, M.D., M.P.H.
Angela Alexander - Mailing List Jimmy Clanton, Jr. - Graphics
Georgia Department of Human Resources
Division of Public Health Epidemiology Branch Two Peachtree St., N.W. Atlanta, GA 30303-3186 Phone: (404) 657-2588 Fax: (404) 657-2608
Please send comments to: Gaepinfo@dhr.state.ga.us
The Georgia Epidemiology Report is a publication of the Epidemiology Branch,
Division of Public Health, Georgia Department of Human Resources

Vaccine Update for the 2000-2001
Influenza Season
Lower than anticipated production yields for the influenza A (H3N2) component of the trivalent influenza vaccine and other manufacturing problems are leading to a substantial delay in the distribution of influenza vaccine and could result in fewer doses of vaccine than last year. Based on recommendations made by the Advisory Committee on Immunization Practices (ACIP) and the Centers for Disease Control and Prevention (CDC), the Georgia Division of Public Health suggests the following guidelines to ensure the optimal use of the available influenza vaccine supply:
Vaccinate individuals at high risk for complications from influenza (see Table 1) Vaccinate healthcare workers who directly care for and have close contact with
persons at high risk for complications of influenza (healthcare workers could introduce influenza to patients, especially in closed communities such as nursing homes) Vaccinate close contacts (including children aged 6 months and older) of persons in high-risk groups (these individuals could transmit influenza to high risk persons)
Once influenza vaccine is available locally, routine vaccination of high-risk persons and their contacts should proceed normally, especially for high-risk young children who are receiving influenza vaccine for the first time and require two doses. Unvaccinated persons should still be offered vaccine even after influenza activity has been detected in a community, as long as vaccine is available. Vaccine can be administered throughout the duration of the flu season. For healthy individuals, it takes approximately two weeks to develop peak immunity after vaccination.
Vaccination of the general population should be delayed until late November or early December to ensure that priority high-risk groups receive vaccine. Scheduling of large, organized vaccination campaigns should also be delayed until late November or early December. Influenza vaccine purchasers are advised not to place duplicate orders with multiple companies. This will minimize the amount of vaccine that is left unused.
**Please note that the delay and possible shortage of influenza vaccine does not apply to pneumococcal polysaccharide vaccine. Individuals at high risk for influenza-related complications should receive pneumococcal vaccine according to the ACIP recommendations published in the April 4, 1997 MMWR.**
An Overview of Influenza Surveillance in Georgia
Each year from October 1 to May 31, Georgia monitors influenza activity throughout the state via a sentinel physician surveillance network, which is a component of the larger network coordinated by the CDC. These data provide a picture of influenza virus activity, the geographic distribution of influenza viruses, and the impact of influenza in different age groups. The surveillance system cannot be used to determine how many people have become ill with influenza during a given season, nor to project or derive rates of influenza infection in the general population.
For the 1999-2000 influenza season, approximately 70 Georgia physicians volunteered to report each week on the total number of patients seen and the number of those patients with influenzalike illness (ILI) by age group. Influenza-like illness is defined as fever greater than or equal to 100 F AND cough and/or sore throat. Participating physicians were also asked to submit throat swabs from representative patients several times during the season. This provides a sample of influenza isolates to allow characterization of strain types, which guide empiric therapy and facilitate planning for future vaccines.
Summary of the 1999-2000 Influenza Season in Georgia
Last season, influenza virus was first isolated at the Georgia Public Health Laboratory (GPHL) in November 1999. Influenza activity in Georgia began to increase in mid-December 1999 and peaked during the week ending January 9, 2000. The percentage of patient visits to Georgia sentinel physicians for ILI increased above baseline levels (0-3%) to 4% during the week ending

December 25, 1999, and remained elevated for six consecutive weeks. The proportion of visits for ILI peaked at 6% during the week ending January 9, 2000 and returned to baseline levels by the week ending February 5, 2000.

target group for influenza vaccination includes persons who are at high risk for serious complications from influenza, including persons aged >65 years and persons aged <65 years who have chronic underlying medical conditions.

Of the 112 throat swabs submitted by sentinel physicians in Georgia, 53 were Biology of Influenza

positive for influenza (47%). All viruses isolated were influenza type A. All

49 influenza A viruses that were subtyped, were A (H3N2) viruses. CDC Influenza A and B are the two types of influenza viruses that cause epidemic

antigenically characterized 19 influenza viruses from the GPHL during the flu human disease. Influenza A viruses are further categorized into subtypes based

season. All were similar to the vaccine strain A/Sydney/05/97; thus, the on two surface antigens: hemagglutinin (H) and neuraminidase (N). Although

1999-2000 influenza vaccine strains were well matched to the circulating both influenza A and B viruses undergo continual antigenic change (i.e.,

influenza virus strains in Georgia. Nationwide, this was the third consecutive antigenic drift), influenza B viruses undergo antigenic drift less rapidly and are

season that influenza A/Sydney/05/97-like (H3N2) viruses were the most not divided into sub-types. Since 1977, influenza A (H1N1) viruses, influenza

frequently isolated influenza viruses in the United States (US).

A (H3N2) viruses, and influenza B viruses have been in global circulation.

_____________________________________________________________

A persons immunity to the surface antigens, especially hemagglutinin, reduces

The following summary of ACIP and CDC recommendations on the preven- the likelihood of infection and the severity of disease if infection occurs.

tion and control of influenza contains excerpts from MMWR April 14, 2000/ vol. 49/No. RR-3 and MMWR July 14, 2000/49(27); 619-622. The complete reports and other information on influenza can be accessed at
http://www.cdc.gov/ncidod/diseases/flu/fluvirus.htm.

However, antibody against one influenza virus type or subtype confers little or no protection against another virus type or subtype. The frequent development of antigenic variants through antigenic drift is the virologic basis for seasonal epidemics and the reason for the incorporation of one or more new

Introduction

strains in each years influenza vaccine.

Epidemics of influenza occur during the winter months nearly every year and Clinical Symptoms of Influenza

are responsible for an average of approximately 20,000 deaths per year in the US. Influenza viruses also can cause global epidemics of disease, known as pandemics, during which rates of illness and death from influenza-related complications can increase dramatically. Influenza viruses cause disease in all age groups. Rates of infection are highest among children, but rates of serious illness and death are highest among persons aged >65 years and persons of any age who have medical conditions that place them at high risk for complications from influenza. Influenza vaccine is the primary method for preventing influenza and its more severe complications. The primary

Typical influenza symptoms include fever, dry cough, sore throat, runny or stuffy nose, headache, muscle aches, and extreme fatigue. Illness typically resolves after several days for most persons, although cough and malaise can persist for two or more weeks. The incubation period is 1-4 days with an average of 2 days. Adults can be infectious starting the day before symptoms begin extending through approximately 5 days after illness onset; children can be infectious for a longer period. In some persons, influenza can exacerbate underlying medical conditions (e.g., pulmonary or cardiac disease) or lead to secondary bacterial pneumonia or primary influenza viral pneumonia.

Table 1. An Overview of Influenza Surveillance in Georgia
Persons at High Risk for Influenza-Related Complications:
Persons aged 65 years or older The 2000 ACIP recommendations lowered the age for universal vaccination from 65 years to 50 years; however, in the context of vaccine delays and a possible shortage this season, contingency plans for persons aged 50-64 years old should focus on vaccinating individuals with high-risk conditions rather than the entire 50-64 year old age group
Residents of nursing homes and other chronic-care facilities that house persons of any age who have chronic medical conditions Adults and children aged 6 months and older who have chronic pulmonary or cardiovascular disease, including asthma Adults and children aged 6 months and older who have required regular medical follow-up or hospitalization during the preceding year because of
chronic metabolic diseases (including diabetes mellitus), kidney dysfunction, blood disorders (hemoglobinopathies), or immune system problems (immunosuppressed or immunocompromised) Children and teenagers (aged 6 months to 18 years) who are receiving long-term aspirin therapy and therefore might be at risk for developing Reye syndrome after influenza infection Women who will be in the second or third trimester of pregnancy during the influenza season

Persons Who Can Transmit Influenza to Those at High Risk:
Physicians, nurses, and other personnel in both hospital and outpatient-care settings, including emergency response workers Employees of nursing homes and chronic-care facilities who have contact with patients or residents Employees of assisted living and other residences for persons in high-risk groups Persons who provide home care to persons in high-risk groups Household members (including children) of persons in high-risk groups

Other Persons:
Pregnant women* Persons Infected with Human Immunodeficiency Virus* Breastfeeding Mothers* Travelers* General Population*

Persons Who Should Not be Vaccinated:
Persons known to have anaphylactic hypersensitivity to eggs or to other components of the influenza vaccine without first consulting a physician* Persons with acute febrile illness usually should not be vaccinated until their symptoms have abated*
*See MMWR April 14, 2000/vol. 49/No. RR-3 and MMWR July 14, 2000/49(27); 619-622. The complete reports and other information on influenza can be accessed at http://www.cdc.gov/ncidod/diseases/flu/fluvirus.htm.

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Options for Controlling Influenza
In the US, the main option for reducing the impact of influenza is immunoprophylaxis with inactivated (i.e., killed-virus) vaccine. Vaccinating persons at high risk for complications before the influenza season each year is the most effective means of reducing the impact of influenza. When vaccine and epidemic strains are well matched, achieving high vaccination rates among persons living in closed settings (e.g., nursing homes and other chronic-care facilities) and among staff can reduce the risk for outbreaks by inducing herd immunity. Vaccination of health-care workers and other persons in close contact with persons in high-risk groups can also help reduce transmission of influenza and subsequent influenza-related complications.
Use of antiviral medications for the prevention of influenza can be highly effective in specific individuals or in certain situations, such as the control of influenza outbreaks in nursing homes. However, widespread routine use of antiviral drugs for chemoprophylaxis against influenza is an untested and expensive strategy that could result in large numbers of people experiencing adverse effects.

treatment for persons aged >12 years, and oseltamivir was approved for treatment for persons aged >18 years.
Control of Influenza Outbreaks in Institutions
Most published reports on the use of amantadine or rimantadine to control institutional outbreaks of influenza A are based on studies of nursing home populations. When confirmed or suspected outbreaks of influenza A occur in institutions that house persons at high risk, chemoprophylaxis (using amantadine or rimantadine as appropriate) should be started as early as possible to reduce the spread of the virus. Chemoprophylaxis should be administered to all residents regardless of whether they received influenza vaccine during the previous fall and should continue for at least 2 weeks or until approximately 1 week after the end of the outbreak. The dosage for each resident should be determined individually. Chemoprophylaxis also can be offered to unvaccinated staff who provide care to persons at high risk. Prophylaxis should be considered for all employees, regardless of their vaccination status, if the outbreak is caused by a variant strain of influenza A that is not well matched by the vaccine.

Composition of the 2000-2001 Influenza Vaccine
The trivalent influenza vaccine prepared for the 2000-2001 season will include A/Moscow/10/99 (H3N2)-like, A/New Caledonia/20/99 (H1N1)-like, and B/Beijing/184/93-like antigens. For the A/Moscow/10/99 (H3N2)-like antigen, US manufacturers will use the antigenically equivalent A/Panama/ 2007/99 (H3N2) virus. For the B/Beijing/184/93-like antigen, they will use the antigenically equivalent B/Yamanashi/166/98 virus. These viruses will be used because of their growth properties and because they are representative of currently circulating A (H3N2) and B viruses.

To limit the potential transmission of drug-resistant virus during institutional outbreaks, measures should be taken to reduce contact as much as possible between persons taking antiviral drugs for treatment and other persons, including those taking chemoprophylaxis. Other outbreak control measures include instituting droplet precautions and establishing cohorts of patients with confirmed or suspected influenza, reoffering influenza vaccine to unvaccinated staff and patients, restricting staff movement between wards or buildings, and restricting contact between ill staff or visitors and patients.
The Role of Laboratory Diagnosis

Strategies for Implementing Vaccine
Recommendations in Health-Care Settings
Successful vaccination programs combine publicity and education for healthcare workers and other potential vaccine recipients, a plan for identifying persons at high risk (usually by medical record review), use of reminder/recall systems, and efforts to remove administrative and financial barriers that prevent persons from receiving the vaccine. Efforts should particularly target settings such as nursing homes and other residential long-term care facilities, visiting nurses and others providing home care to persons at high risk, assistedliving facilities, retirement communities, and recreation centers. For more complete information on identifying and vaccinating persons for whom influenza vaccine is recommended, please consult the MMWR April 14, 2000/ vol. 49/No. RR-3 and MMWR July 14, 2000/49(27); 619-622.

The early diagnosis of influenza can help reduce the inappropriate use of antibiotics and provide the option of using antiviral therapy. However, because some bacterial infections can produce symptoms similar to those of influenza, bacterial infections should be considered and appropriately treated if suspected. In addition, bacterial infections can occur as a complication of influenza.
Despite the availability of commercial rapid diagnostic tests, the collection of clinical specimens for viral culture is important because only culture isolates can provide specific information on circulating influenza subtypes and strains. This information is needed to compare current circulating influenza strains with vaccine strains, to guide decisions about influenza treatment and prophylaxis, and to formulate vaccine for the coming year. Virus isolates also are needed to monitor the emergence of antiviral resistance.

Recommendations for the Use of Antiviral Agents
for Influenza
Four currently licensed agents are available in the US: amantadine, rimantadine, zanamivir, and oseltamivir. The drugs differ in terms of their pharmacokinetics, side effects, and costs. Please consult the MMWR April 14, 2000/vol. 49/No. RR-3 for an overview of the indications, use, administration, and known primary side effects of these medications. Readers should also consult the package inserts for more complete information.

Sources of Information on Influenza
Georgia Epidemiology Branch: 404-657-2588 and http://health.state.ga.us/epi/ Georgia Immunization Program: 404-657-3158 and http://health.state.ga.us/programs/immunization/index.shtml CDC Voice Information System (influenza update): 888-232-3228 CDC Influenza Branch: http://www.cdc.gov/ncidod/diseases/flu/weekly.htm.

Amantadine and rimantadine are chemically related antiviral drugs with activity against influenza A viruses, but not influenza B viruses. Amantadine was approved in 1966 for prophylaxis of influenza A (H2N2) infection and was later approved in 1976 for the treatment and prophylaxis of influenza type A virus infections in adults and children aged >1 year. Rimantadine was approved in 1993 for treatment and prophylaxis of infection in adults.
Zanamivir and oseltamivir are neuraminidase inhibitors with activity against both influenza A and B viruses. Both zanamivir and oseltamivir were approved in 1999 for the treatment of uncomplicated influenza infections, but neither has yet been approved for prophylaxis. Zanamivir was approved for

Thanks to the Influenza Sentinel Physician
Surveillance Network
The Georgia Division of Public Health would like to thank the 70 medical providers statewide who volunteered to participate in the influenza surveillance network for 1999-2000. Thanks to you, we were able to identify the onset of the influenza season in Georgia, detect widespread onset of influenza A outbreaks, and determine influenza strains occurring locally. For more information about participation in the surveillance network, or to report outbreaks of influenza-like illness, please contact Laurel Boykin Murrow, Influenza Surveillance Coordinator at 404-657-2588.

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

Bulk Rate U.S. Postage
Paid Atlanta, Ga Permit No. 4528

November 2000

Volume 16 Number 11

Reported Cases of Selected Notifiable Diseases in Georgia Profile* for August 2000

Selected Notifiable Diseases

Total Reported for August 2000
2000

Previous 3 Months Total

Ending in August

1998

1999 2000

Previous 12 Months Total

Ending in August

1998

1999

2000

Campylobacteriosis

46

Chlamydia trachomatis

3553

Cryptosporidiosis

22

E. coli O157:H7

6

Giardiasis

76

Gonorrhea

2266

Haemophilus influenzae (invasive)

2

Hepatitis A (acute)

39

Hepatitis B (acute)

11

Legionellosis

0

Lyme Disease

0

Meningococcal Disease (invasive)

0

Mumps

0

Pertussis

2

Rubella

0

Salmonellosis

196

Shigellosis

20

Syphilis - Primary

11

Syphilis - Secondary

32

Syphilis - Early Latent

39

Syphilis - Other**

68

Syphilis - Congenital

1

Tuberculosis

66

253

204

210

5209

8768

8652

43

36

63

54

19

29

351

379

306

5281

6206

5679

13

18

11

214

124

97

40

72

59

5

1

2

1

0

0

17

11

6

0

2

0

13

20

10

0

0

0

700

693

634

410

85

65

26

47

29

44

74

80

187

152

121

248

195

171

7

3

2

167

180

178

839 15336
117 69 1143 13548 57 853 247 12 9 101 2 30 0 1587 1448 133 263 917 969 13 619

768 31398
187 49 1325 21669 84 682 198 1 0 75 4 47 0 1966 485 141 270 773 747 18 626

639 30481
178 57 1291 20259 78 325 241 10 0 60 3 52 0 1831 274 128 310 605 717 18 679

* 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
Latest 12 Months: 9/99 - 8/00 Five Years Ago: 9/94 - 8/95 Cumulative: 7/81 - 8/00

Total Cases Reported*

Percent Female

AIDS Profile Update
Risk Group Distribution (%) MSM IDU MSM&IDU HS Blood

Unknown

1285

27.3

29.1

10.9

2.5

13.6

1.8

42.1

2416

18.3

47.4

21.5

5.7

14.4

1.8

9.2

22266

16.5

49.1

18.6

5.7

12.9

1.9

11.9

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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Race Distribution (%) White Black Other

19.8 77.4

2.8

36.2 61.5

2.3

36.2 61.7

2.1