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The Vac-Scene Newsletter
Volume 7, No. 1 - January-February 2001
Update: Measles in King County
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The measles outbreak in King County continues, with 11 cases confirmed since mid-January. Multiple and significant public exposures have occurred. It is important now to assess the measles immunity of patients born in 1957, or later, and to provide a dose of measles-containing vaccine to those patients who lack: 1) a reliable history of immunity (e.g. from natural measles infection or from vaccination), or 2) documentation of a dose of measles-containing vaccine given at age one year or older, in or after 1968. It is also important to prepare for the management of patients suspected to have measles or who have had recent exposures to measles.
Measles (rubeola) is an acute disease characterized by an initial prodrome including temperature of 101°F or higher, and a respiratory syndrome of cough, coryza, conjunctivitis, followed by an erythematous, maculopapular rash beginning on the face and spreading to the trunk and extremities. Koplik spots may appear on the buccal mucosa. Measles complications include otitis media, bronchopneumonia, and acute encephalitis.
The King County cases occurred in two separate clusters, one in southwest King County, and a second cluster at Northwest School for the Arts and Humanities in Seattle. At this time we are aware of no link between these two initial clusters. The most recent cases have also not been linked to the initial clusters, implying significant community exposure to the virus. The cluster at the Northwest School has been traced to the travels of a non-immune student to Korea, where a large measles outbreak is underway. Upon return to school in Seattle, the fell ill with measles and attended class while contagious. Three additional cases subsequently occurred among students at the school.
In the Southwest King County cluster, three of the four cases attended the same showing of a movie at SeaTac North Cinemas in Federal Way on 12/31. The fourth case is a 14-month-old who is frequently taken to stores in Federal Way, including SeaTac Mall. Subsequently the 39-year-old grandparent of this case developed measles.
The two most recent cases are adults not directly linked to either cluster. The cases have potentially exposed patients and staff to measles at several health care facilities.
King County has not reported more than 10 cases of measles since 1991, and fewer than six cases per year had been reported until 2001. In all of the intervening years, fewer than 6 cases per year were reported per year. In the current outbreak, the public exposures have been diffuse, and numerous, making it difficult to target preventive efforts and increasing the likelihood of transmission of disease especially among young adult contacts. Cases have ranged in age from 14 months to 39 years. Four of the eleven cases are adults, 32 to 39 years of age, who have no confirmation of their measles immune status. Measles disease in adults who were born between 1957 and 1968 is not unusual. These adults grew up at a time when exposure to measles disease was less likely, and when childhood coverage with live measles vaccine was significantly lower than today. The live measles vaccine was not available until 1968.
Health care providers are requested to assess the measles immunity of staff and patients and to consider the appropriate infection control and management plan for suspected measles cases. Health care workers born in 1957 or later should have documentation of two doses of measles vaccine given in 1968 or later.
To access free, accurate, and expedited laboratory results, all laboratory specimens should be submitted to the Washington State Department of Health Laboratories after reporting the case to Public Health at 206-296-4774.
For staff or patients who are suspected to have measles, please collect the following specimens for diagnosis: 3-5 cc. of blood in a red or tiger topped tube for serology (IgG and IgM) and a urine specimen for culture. Prompt reporting and laboratory confirmation improves the opportunity to provide post- exposure prophylaxis to susceptible contacts. All susceptible contacts may be offered measles vaccination within 72 hours, and high-risk contacts may be treated with immune globulin for six days, to prevent measles disease.
For up-to-date information on the status of the measles outbreak in King County, visit Public Health's website at www.metrokc.gov/health/news/press.htm. The following measles immunization fact sheets are available for you to provide to your adult and pediatric patients:
News from the Public Health vaccine distribution program
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- Publicly-funded pneumococcal conjugate vaccine (pcv) now available
Prevnar, the pneumococcal conjugate vaccine manufactured by Wyeth-Lederle, was made available to Washington State health care providers for children <5 years through the Vaccines For Children (VFC) program in January 2001. An announcement detailing this change was sent to providers who receive VFC vaccines in King County, along with the annual request to renew VFC Provider Agreements. If you would like another copy of this announcement about Prevnar, please call 206-296-4782.
- Reminder: 2001 provider agreements due
Most clinics have returned their new 2001 Provider Agreements, but there are still a few Agreements that have not yet been received. Vaccine orders cannot be processed after Febuary 16th until the Agreement has been received by the Immunization Program. Questions? Call 206-296-4782.
- National Td shortage continues
The national shortage of tetanus-diphtheria vaccine (Td) for adults is likely to go on for many months. Last Spring, Wyeth Lederle, one of the two manufacturers of Td, temporarily fell behind in production. Recently, however, Wyeth-Lederle, announced that they will no longer supply the adult or pediatric formulations of tetanus-diphtheria vaccine (Td and DT). The sole remaining manufacturer of Td and DT in the United States is now Aventis Pasteur. It is unclear how long it will take for them to replenish supplies of the Td vaccine, but it is likely that the shortage will continue throughout the year. The VFC program is doing everything possible to obtain adequate supplies of Td to assure that those who need the vaccine most can get it.
State-supplied Td vaccine has been permanently restricted for use in children ages 7 years through 18 years. In addition, state-supplied Td remains extremely limited, so you may receive only a portion of the amount ordered. Providers are strongly encouraged to establish protocols to prioritize the use of Td. The CDC recommendations for prioritizing the use of this vaccine are still in effect. Call the Immunization Program at 206-296-4774 or visit the following website for more information: www.cdc.gov/mmwr/preview/mmwrhtml/mm4945a3.htm
- New usage reports and temperature logs
The Temperature Logs and Private Provider's Report of Vaccine Usage have been updated by the Washington State Department of Health (DOH), and soon they will be available from the DOH materials warehouse. The new forms can be obtained by calling DOH at 360-664-8688. The new temperature log will have two places to record temperatures: 1) a written numeric temperature, and 2) a graphed temperature. Instructions for completing the new log are on the form. The primary change in the Report of Vaccine Usage is the addition of PCV.
- Reminder: Benchmarking in May 2001
This year, the Immunization benchmarking project will be conducted during the month of May (instead of August). All heath care providers receiving state-supplied vaccine are required to participate in this benchmarking activity. This statewide survey provides valuable information needed for continued federal funding to purchase vaccine. Training materials and supplies will be provided in the coming months.
Your participation is greatly appreciated.
National immunization survey results
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The latest immunization rates have been released by CDC for children 19-35 months of age, for the period July 1999-June 2000. A table below shows the latest results by antigen. Complete tables are available at CDC's website: www.cdc.gov/nip/coverage/data.htm.
Immunization rates for King County have risen slightly from 1999, but the combined rates are still below what they were in 1998. For the 4-3-1-3 combination rate, King County is 78.7±5.1, compared to 77% nationally. King County is third in the country compared to other large urban areas (after Boston and Jefferson Co., Alabama), but only 1.5 percentage points above national average. The national goal is for 90% of children to be complete for immunizations by their second birthday.
What is notable for King County is that from 1998 to this latest report, polio vaccine rate is low (85.9±4.5 for Pol-3) as is the 4th DTP/DTaP (82.6±4.8).
For polio vaccine, the issue seems to be threefold (as reported by providers we talked to last summer): 1) confusion caused by the changes in the recommended schedule (from OPV-alone to sequential IPV/OPV, and finally to IPV-only); 2) new cases of wild polio disease are not occurring in the western hemisphere, hence the perception that polio vaccine is less important than others given at this age, and 3) because there are several vaccines recommended for children at this age, polio vaccine is often dropped or deferred.
Historically, we have seen a decline in immunization coverage rates because of an incomplete four-dose DTaP series. DTaP coverage rates drop dramatically from DTaP-3 to DTaP-4 (see Table below). The issue of parent/provider reluctance regarding multiple injections may be a contributing factor. As new vaccines are introduced into the schedule (e.g. pneumococcal conjugate vaccines), the challenge of administering multiple injections will continue.
Use of varicella vaccine is increasing steadily, but it is still low at 47.5±6.0. The low rate is probably caused by the unique storage requirements and the mixed support for the vaccine when it was first recommended.
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NATIONAL IMMUNIZATION SURVEY 7/99-6/00
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US National
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Washington
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King County
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3+DTP
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95.1±0.5***
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95.2±1.8
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92.8±3.5
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4+DTP
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82.8±0.8
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81.3±3.6
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82.6±4.8
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3+Polio
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89.7±0.6
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89.0±2.8
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85.9±4.5
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1+MMR
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90.6±0.6
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89.7±2.8
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89.3±4.0
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3+Hib
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93.6±0.5
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93.6±2.2
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90.7±3.9
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3+HepB
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90.3±0.6
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89.0±2.8
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82.5±4.9
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1+Var
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62.7±1.0
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41.2±4.4
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47.5±6.0
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3:3:1
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84.8±0.8
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84.2±3.3
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82.2±4.9
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4:3:1
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78.9±0.9
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77.5±3.8
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79.5±5.1
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4:3:1:3
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77.3±0.9
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76.1±3.9
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78.7±5.1
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4:3:1:3:3*
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73.7±0.9
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72.2±4.1
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71.2±5.7
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*Four or more doses of DTP, three or more doses of poliovirus vaccine, one or more doses of any MCV (measles-containing vaccine), three or more doses of Hib, and three or more doses of Hep B.
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Minimum age and intervals matter when you vaccinate!
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Each vaccine has a minimum acceptable age of administration for at least the first dose in the series. In addition, minimum acceptable intervals exist between doses within a vaccine series. These minimum ages and intervals are based on data gathered during clinic trials of each vaccine prior to its licensure. The safety and efficacy of vaccines which are administered outside of these minimum guidelines are not supported by clinical data. The ACIP "General Recommendations on Immunization" (MMWR, 1994;43:No.RR-1) states that doses given at less than the minimum interval should not be counted as part of the series.
Recent assessment of providers' documentation of immunization records by Public Health's Immunization Program staff have revealed several issues:
- Hepatitis B vaccine:
Doses #2 and #3 in the hepatitis B series are often given too soon. For all ages, there must be at least 4 weeks between dose 1 and dose 2, and at least 4 months between doses 1 and 3. In addition, in infants, dose 3 should not be given earlier than 6 months of age. Poorer immune response rates are seen in infants who complete the hepatitis B vaccination series prior to 6 months of age.
- Hepatitis A vaccine:
The minimum age to receive hepatitis A vaccine is 2 years.. Many clinics are administering this vaccine too early! It is not licensed for children under 2 years of age. There are insufficient data from clinic trials to show efficacy or safety prior to this age. If a child younger than two years is travelling abroad and needs protection against hepatitis A virus, providers can administer immune globulin (IG) for short-term protection (lasting approximately 3 months).
- Hib (haemophilus influenzae type b) vaccine:
Administering the first dose of Hib vaccine before the minimum age of 6 weeks may induce immunologic tolerance to additional doses of Hib vaccine! In other words, a dose given before 6 weeks of age may make the child incapable of responding to subsequent doses.
Why do some vaccination rules say months and some say weeks for minimum intervals?
The choice of describing intervals using week or month terminology is often based on the preference of the person writing the ACIP Statement, or the way the interval was described in prior Statements. The ACIP Statement on measles, mumps and rubella vaccines from May 1998 was the first one to operationally define a month as 28 days. This definition now allows immunization registries to define when to recall a child for the next dose of vaccine. Generally a month is described as 4 weeks or 28 days, two months is 8 weeks, and after that the intervals are defined as months. Call 206-296-4774 and ask to speak with an Immunization Nurse if you have questions!
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key sites
Measles fact sheet
Measles is a respiratory disease caused by a virus that normally grows in the cells that line the back of the throat and in the cells that line the lungs.
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