2114
Rubeola.
Highly infectious acute viral disease that can cause rash, fever, diarrhea, encephalitis and death.
A leading cause of morbidity and mortality, worldwide, particularly in regions with low immunization levels.
In 2023 an estimated 107,500 deaths occurred worldwide due to measles: mostly among children younger than five years.
The prodrome is followed by a high fever and the generalized rash that spreads centripetally from face to trunk to limbs along with malaise, lethargy and pathognomonic Koplik spots on the buccal surfaces of the oral mucosa.
An erythematous, macularpapular rash appears five days after initial symptoms: it starts at the hairline and spreads to the face trunk and extremities.
The rash is initially blanching and then may turn brown and desquamate and last approximately one week.
Overall 60 to 70% of patients with measles develop complex spots, small blue to white lesions inside the mouth which appear transiently one to two days before the characteristic rash and are pathognomonic features of measles.
Single stranded, enveloped RNA virus.
Genus morbillivirus in Paramyxoviridae family of viruses.
Transmitted primarily by means of respiratory droplets and small particle aerosols that can remain viable in the air for up to two hours.
People with the infection typically can transmit the virus four days before and four days after the eruption of the rash.
In 2017 they were 149,142 cases reported worldwide: an estimated 10.3 million persons globally were infected with measles in 2023.
Certified as eliminated in the US in 2000.
In 2022 more than 9 million measles cases of occurred worldwide and an estimated 136,000 people, mostly children died from the highly contagious disease (CDC/WHO).
In 1963, there was an estimated 3 to 4,000,000 cases of measles annually and this is prior to authorization of the first measles vaccine.
It was associated with 400 to 500 deaths and 48,000 hospitalizations.
IN 2023 and 2024 more than 90% of measles cases worldwide were among children in low and middle income countries, and most of these infected were children younger than five years of age with the highest mortality among those younger than one year.
Young infants are at heightened risk for severe measles related complications, such as pneumonia, encephalitis, and death.
In recent measles outbreaks more than 2/3 of unvaccinated individuals who were eligible for vaccination had a non-medical exemption to vaccination.
The Covid-19 pandemic has lowered the vaccination rate with a worldwide coverage of 81%.
The measles vaccination rate in the United States usually is 95 to 97% nationwide and has dropped significantly with Covid-pandemic.
Remains a leading cause of vaccine preventable illnesses and deaths worldwide, that claims more than 100,000 lives each year.
It is estimated that measles vaccination has prevented an estimated 21.1 million deaths.
Universal vaccination resulted in the illumination of endemic measles in the US in the year 2000.
One of the most contagious directly transmitted pathogens, with outbreaks occurring in population in which fewer than 10% of their population are susceptible.
Not a latent or persistent viral infection, and without animal reservoirs makes eradication possible.
Measles virus can be maintained only in humans by an unbroken chain of acute infections.
Maternal Immunity from the wild form of the virus provides passive immunity and protects most infants until their second year of life.
Between 10 and 14 days after exposure, illness starts with a prodromal phase and includes fever, and any of three symptoms – cough, coryza, and conjunctivitis (the three Cs.).
An acute viral illness that starts with a prodromal phase and lasts 2-4 days, of fever and at least one of cough, coryza, and conjunctivitis, and similar to any upper respiratory tract infection.
In the pre vaccine era an average of 10,000 new cases of measles occured every day in the US.
Before the widespread vaccinations for measles, the virus caused 2-3,000,000 deaths globally per year.
Vaccination required for school attendance in every state.
In 2019, there has been a worldwide dramatic increase in infections due to non compliance receiving the MMR vaccine.
Transmission occurs among those who travel to areas where the virus persists, and occasional local transmission occurs.
Infants become susceptible to the virus when passively acquired maternal antibody is lost.
Exposed patients that are not immune have up to a 90% chance of contracting measles, and each person may go on to infect 9-18 other individuals, in a susceptible population.
Infants born to women with vaccine induced immunity are susceptible to measles at a younger age than those infants born to women with naturally acquired immunity.
The average age that people contract measles is related to the rate of decline of maternal bodies, the degree of contact with infected individuals, and the level of measles vaccine coverage in the population.
Endemic in most of the world but has been eliminated in the U.S. because of high rate of vaccination.
Children younger than five years, adults older than 20 years, pregnant women, and people with compromised immune system have the highest risk of measles complications which can include encephalitis and pneumonia.
Pneumonia is the most common cause of death for measles in young children.
In the US, one and five with measles who are unvaccinated require hospitalization
The most common side effects of the measles vaccine include a sore arm and fever.
About 5% of patients who receive the vaccine develop a rash, even the smaller number have a febrile seizure or transient decrease in platelet counts.
Very rarely meningocephalitis may occur as a result of the vaccine, almost always in immunocompromised patients.
Measles vaccination has prevented an estimated 21 million deaths worldwide since the year 2000.
Declared eliminated in 2000 in the US.
Most cases in the US are imported.
MMR vaccine recommended for routine use in all US children at age 12-15 months, with a booster at age 4-6 years.
Children aged 12 months or greater traveling internationally should receive 2 doses of MMR vaccine, separated by at least 28 days, aged 6-11 months should receive 1 dose of MMR vaccine.
One dose of vaccine prevents 93% of cases, while 2 doses prevent 97% of cases.
The degree of immunity can wane, but risk of infection is very low.
EEG changes reported in 50% of uncomplicated cases.
Diagnosis suggested by the presence of fever, maculopapular rash, cough, coryza, or conjunctivitis.
Diagnosis is a challenge during the prodromal phase because the rash may not be visible until 4-7 days after disease onset and how many patients with pre-existing immunity may have a modified pro longed incubation.
Rash develops in a cephalocaudal and centrifugal distribution.
The rash characteristically is erythematous macular papular exanthem appearing 2-4 days after the onset of fever, first on the face and head and then on the trunk and extremities.
The facial rash may be confluent on the face and upper body.
Cough, coryza, and conjunctivitis common.
Koplik ‘s spots are transient and seen in 50-70% of cases: small white spots on the buccal mucosa which are pathognomonic for measles.
The spots may appear one to two days before the onset of rash and last for an additional one to two days after the rash onset.
Headache, and GI symptoms are common.
CSF pleocytosis common.
Causes a variety of central nervous system syndromes, including meningitis, encephalitis, subacute sclerosing panencephalitis and acute disseminated encephalomyelitis.
Acute encephalitis develops in 35 to 100 of 100,000 measles patients.
Mortality rate of acute encephalitis is 10-20%, and neurologic damage occurs in 25% of survivors.
The basic reproduction number, that is, the number of secondary cases generated by one patient with measles ranges from 14 to 18.
The reproduction number is significantly higher than that for other airborne infectious diseases which are approximately 5-7.
Infants born to women with vaccine induced immunity are susceptible to measles at a younger age than those born to women with naturally acquired immunity.
Average age of contraction of measles depends on the rate of decline of protective maternal antibodies, the degree of contact with infected individuals, and the level of measles vaccine coverage.
90% of susceptible patients will develop measles who have close contact with a person with measles.
Viral transmission is by direct contact with infectious droplets by airborne spread.
Aerosolized droplet nuclei have been detected up to 2 hours after a measles patient has been in an area.
Patients with measles infectious 4 days before and after rash.
In urban settings with dense population and low vaccine coverage the disease affects mainly infants and young children.
With increasing measles vaccine coverage, and decreasing population density the age distribution for measles shifts to older children., adolescents and adulthood.
Mortality rate is increased in girls an estimated 5% over boys.
Patients who survive a measles infection remain vulnerable to other potentially deadly infections for as long as two or three years post-infection.
Complications occur in approximately 30% of cases.
Common complications include secondary infections related to induced immunosuppression, diarrhea, keratoconjunctivitis, otitis media, and pneumonia.
Complications frequently occur up to one month after infection and include diarrhea, pneumonia, otitis media, and conjunctivitis.
Pneumonitis and giant cell pneumonia are rare but severe and potentially fatal complications.
Pneumonia is the most common cause of measles related death.
Approximately one in 1000 cases of measles serious, even fatal, neurologic complications, such as encephalomyelitis, may occur.
Children, younger than five years, adults, older than 20 years, immunocompromised individuals, and pregnant individuals are at high risk for complications.
Even after recovery, children who’ve had measles they are high risk for late complication, such as pneumonia, malnutrition, and blindness.
Blindness is usually due to severe corneal, ulceration and particularly in children who are deficient in vitamin A.
Malnutrition, particularly vitamin A deficiency increases the risk of complications, which include diarrhea, otitis media, hearing loss, pneumonia, and blindness from corneal ulcers and scarring.
Approximately one in 10,000 patients develop subacute sclerosing panencephalitist which can occur years after measles virus infection, with a severe, progressive, and fatal course.
The greatest risk of complications related to measles occurs in immunosuppressed individuals.
Overall, 1 to 3 per 1000 people die of measles.
Complications during pregnancy include miscarriage, premature birth, low birthweight, and stillbirth.
Immunosuppression due to measles infection last up to 2 to 3 years with increased risk of secondary bacterial and viral infections.
Immunosuppressed patients may have atypical presentations with severe complications.
Patients with significant immunosuppression cannot be safely vaccinated with the live-attenuated vaccine and must rely on herd immunity to protect them from measles infection.
Malnutrition and measles or linked with exacerbation of vitamin A deficiency and a poor response to measles vaccine,and death.
Elevated liver functions care in 2/3 of patients in adult patients.
Tests such as a positive anti-measles virus IgM results or a four fold increase in levels of anti-measles virus IgG helpful in the diagnosis.
Measles specific IgM antibody is typically detected 3 to 30 days after rash onset.
Measles specific IgG antibodies, are not detectable until at least seven days after rash onset and indicates immunity due to previous infection of vaccination.
Detection of RNA measles virus by polymerase chain reaction allows genotype identification and helps distinguish wild type measles from vaccine associated measles during outbreaks.
A throat swab or nasopharyngeal swab for measles RNA by reverse transcriptase polymerase chain reaction should be obtained on all patients suspected to have measles, and adding urine PCR increases sensitivity.
Viral RNA is detectable for about three days after rash onset, with a sensitivity of 94% and the specificity of 99%.
Vaccine failure is divided into two categories: primary failure results from a lack of initial seroconversion, and secondary failure results from a loss of immunity after initial seroconversion.
Vaccination with 2 doses of measles-mumps -rubella vaccine recommended for children, with first dose at 12-15 months and second dose 4-6 years, before school entry.
Immunization with measles, mumps, and rubella vaccine is highly effective, providing immunity against measles in approximately 93% of individuals after the first dose and 97% after two doses.
Two doses of vaccine recommended for unvaccinated adults at exposure risk, and 1 dose for other adults 18 years or older.
In unvaccinated or under vaccinated, persons, measles vaccine is recommended within 72 hours after exposure.
When there are contraindications to the measles vaccine – immunocompromised or pregnant persons or infants younger than six months of age, human immune globulin is recommended to be given within six days after exposure.
The estimated effectiveness of post exposure prophylaxis for the prevention of measles ranges from 76% to 100% with immune globulin and from 83% to 100% with the measles vaccine.
The effectiveness of post exposure, prophylaxis may be affected by the concentration of measles antibodies in immune globulin products which has been decreasing.
Measles vaccines contain Mumps-rubella (MMR), and Measles-Mumps-rubella-varicella (MMRV) vaccine.
MMR vaccine practices include immunizing all children with two doses of vaccine, the first dose 12 to 15 months of age and the second dose at 4 to 6 years of age.
Standard and airborne precautions should be implemented, including isolating patients to negative pressure rooms.
No specific antiviral therapy is currently available.
Ribavirin shows in vitro activity against measles virus, but is not approved for treatment.
Vitamin A is recommended for all infants and children hospitalized with measles.
In the US hospitalized children with measles frequently have low serum vitamin A levels, correlating with measles severity.
Vitamin A is critical enhancing immune responses against infections.
Measles can occur in persons who are fully vaccinated, or who are under vaccinated.
Such breakthrough infections can result from primary vaccine failure, lack of serum conversion after immunization, or secondary vaccine failure due to waning of the measles antibody level, which can occur six or more years after vaccinations.
Individuals with primary vaccine failure may have a classic measles syndrome, but with secondary vaccine failure, there is usually a milder symptom pattern, and less contagion.
Worldwide, measles cases have dramatically increased in recent years, and the primary cause of the resurgence is failure to vaccinate, not failure of the vaccine.