MEASLES (RUBEOLA)

 

Identification:

 

Acute, highly communicable viral disease with fever, conjunctivitis, coryza (nasal discharge), cough, and koplik spots on the mucosa of the mouth.  A red, blotchy rash appears on the third to seventh day, beginning on face, becoming generalized and lasting four to seven days.  More severe in infants and adults than in children.  Complications such as otitis media and bronchopneumonia occur in 10% or reported cases (even more commonly in those who are poorly nourished and chronically and in infants< 1 year) and encephalitis occurs in approximately 1 of every 1,000 reported cases. In Canada a death is estimated to occur in every 3000 cases.

 

Infectious Agent:   

 

Measles virus.

 

Reservoir:

 

Humans.

 

Incubation Period:

 

Seven to 18 days- usually about ten days until fever develops and 14 days until rash appears. Immune globulin given for passive protection later than the third day of the IP may extend this period.

 

Period of Communicability:

 

From one day prior to the beginning of the prodromal period (usually 4 days prior to rash), four days after appearance of rash- minimal transmission after second day of rash.

 

 

Geographical Distribution:

 

Countries having higher levels of reported measles activity since January 2002 include: Columbia, Venezuela, Denmark, Italy (Campania region), Guam and Papua- New Guinea.

In 2002, 17 African countries (Benin, Cameroon, Cote d’Ivoire, Democratic Republic of the Congo, Ghana, Guinea, Kenya, Lesotho, Liberia, Malawi, Rwanda, Senegal, Swaziland, Uganda, United Republic of Tanzania, Zambia and Zimbabwe) planned mass measles campaigns targeting 75 million children.

 

 

Mode of Transmission:   

 

Airborne by droplet spread, direct contact with nasal or throat secretions of infected persons, and less commonly, by articles freshly soiled with nose and throat secretions. In temperate climates it occurs primarily in late winter and early spring. In tropical climates it occurs mainly during the dry season.

 

 

 

 

 

 

Susceptibility:

 

All persons who have not had the disease or been successfully immunized are susceptible.  Acquired immunity after disease is permanent.  Immunization after first birthday is recommended.  Infants born of mothers who have had the disease are immune for approximately six to nine months.  Children borne to mothers with vaccine induced immunity receive less passive antibodies.

 

Prevention:

 

Immunization with live attenuated measles in the combined MMR vaccine at 12 months of age with a repeat booster at 4 to 6 years of age.

Routine immunization is recommended for adults born after 1970 without a history of disease. This cut off was changed from the previous 1957 cut off in the 1998 Canadian Immunization Guide because of the epidemiology if the disease. In Canada the vaccine was not used widely until the early 70’s and the age of administration was 12 months while the States began immunization in the 60’s and immunized at 15 months of age.

Most adults without proof of immunity are already immune and a single dose of vaccine will raise that proportion close to 100%. A small proportion of adults born since 1970 are still vulnerable. One additional dose of vaccine should be offered to those at greatest risk of exposure and who have not already received two doses or had natural protection: travellers to an endemic area, health care workers, students at post- secondary institutions, military recruits and adults who are aware they were never immunized.

Measles live vaccine was introduced in 1963. Despite high vaccine coverage between 1989 ands 1995 there were many large outbreaks. It was estimated that 10 to 15 % of immunized children remained susceptible related to vaccine interference by persisting maternal antibodies, hence the move to a two dose schedule.

Two doses of vaccine given 4 weeks apart are recommended for children who are out of step with the routine schedule, are without an immunization record, are without reliable records of immunization ( immigrants), were given vaccine and IG simultaneously or vaccine within 5 months of receiving IG or if they received an inadequate dosage.

MMR can be given as early as 6 months of age if infant travelling to an endemic area. Under these circumstances such children should receive two additional doses of MMR after the first birthday!

If an unimmunized individual is exposed, administering measles vaccine within 72 hours may offer some protection.

IG may be used within 6 days after exposure for susceptible household or other contacts for whom risk of complications is very high ie. those under 1 year, pregnant females, immunocompromised individuals or for those whom measles vaccine is contraindicated. Dose is 0.25ml/kg to a max of 15 ml- for the immunocompromised dose is 0.5 ml/kg.

Eradication of this disease in the western hemisphere is targeted for the end of 2005.

 

 

PREPARATIONS:

 

Available- live attenuated measles vaccines are available alone form Aventis or as MR combination form Swiss seum or as MMR combination as MMR 11 from Merck or as Prioix from GSK. They are generally prepared in chick fibroblast cell cultures and all preparations may contain traces of antibiotics (e.g. neomycin) and stabilizer such as gelatine. Consult product monographs for specific details!

The dosage is 0.5 ml given subcutaneously.

The vaccine should be stored in the frig between 2 and 8 degrees C and once reconstituted should be administered promptly! The diluent can be stored at room temperature or in the frig.

The vaccine can be given concurrently with other childhood vaccines. Separate injection sites are required at different anatomic sites. When giving other live vaccines they can be given on the same day and if not then separated by a minimum 4-week interval.  Immunization can suppress a positive TST for several weeks therefore if testing is required it should be done on the same day as immunization or delayed 6 weeks or more. There is no evidence that the measles vaccine exacerbates TB as natural measles does. MMR is indicated for most infants infected with HIV whose immune function at 12 t 15 months is compatible with safe MMR immunization- consultation with an expert will determine this. Re-vaccination would be appropriate in those with moderate immunodeficiency if there is a high risk of disease in the community or travel to endemic areas.

The vaccine produces a mild, non-transmissible and usually subclinical infection. For complete details on possible reactions refer to specific product monographs. Egg allergies are no longer considered a contraindication. In those with a history of anaphylaxis to hens’ eggs, vaccination should take place where adequate facilities are available to manage any reaction. Women known to be pregnant should not receive the vaccine. Pregnancy should be avoided for one month following receipt of monovalent vaccine and 3 months following MMR or other rubella containing vaccine. Breastfeeding is not a contraindication for vaccination of mom or infant. MMR vaccine has no effect on antibiotics or antimalarial drugs and the drugs do not reduce the immunogenicity of MMR.