Week 2- Mumps

Question 1

Mumps

Answer 1

A systemic disease characterized by swelling of one or more of the salivary glands (usually the parotid glands). The swelling lasts 3-7 days. Low grade fever, myalgia, anorexia, malaise, and headache may precede parotiditis. Without vaccination, mumps usually occurs during childhood. When infection occurs in adults, complications are more common. The virus can cross the placenta, but there is no congenital malformation

Question 2

How does mumps affect people who are vaccinated?

Answer 2

1 in 5 vaccinated people will be asymptomatic if infected. Symptoms are also milder and complications will be less common among vaccinated people

Question 3

Orchitis

Answer 3

Inflammation of one or both testicles. It is the most frequently reported complication of mumps- occurs in 30% of unvaccinated and 6% of vaccinated men (after puberty). Half of people with mumps orchitis will develop atrophy of the affected testicles

Question 4

Mumps complications (4)

Answer 4

1. Orchitis and atrophy of the affected testicles
2. Cerebral spinal fluid pleocytosis- less than 1% of these people will develop viral meningitis
3. Less common- oophoritis, pancreatitis, encephalitis, hearing loss (either transient or permanent), arthritis, thyroiditis, mastitis, glomerulonephritis,
   myocarditis, endocardial fibroelastosis, thrombocytopenia, cerebellar ataxia, and trans-
   verse myelitis
4. Contralateral parotitis has been observed within weeks to months after recovery

Question 5

Pleocytosis

Answer 5

Increase in white blood cell count observed in body fluids, such as in CSF

Question 6

Mumps etiology

Answer 6

Paramyxovirus is an enveloped single stranded RNA virus in the rubulavirus genus. This genus also includes 2 types of human parainfluenza virus. Other infectious causes or parotitis includes bacterial agents, HIV, and EBV

Question 7

Epidemiology of mumps

Answer 7

Prior to the mumps vaccine, the peak incidence of mumps was between January and May and among children younger than 10. The mumps vaccine was recommended for routine childhood immunization in 1977. After implementation of the 2-dose measles, mumps, and rubella vaccine (MMR) recommendation in 1989 for measles control in the United States, mumps further declined to extremely low levels, with an incidence of 0.1/100 000 by 1999.

Question 8

Transmission of mumps

Answer 8

Humans are the only known host of mumps. The virus is spread through close, direct contact- respiratory tract secretions and saliva

Question 9

Incubation period of mumps

Answer 9

Usually 16-18 days, but cases can occur from 12-25 days after exposure. People are most contagious several days before parotitis onset. Isolation is recommended for 5 days after onset of parotid swelling

Question 10

Mumps diagnostic tests

Answer 10

An RT-qPCR assay can be done on a cheek swab- this is the preferred method of diagnosis, although a negative test doesn’t necessarily rule out diagnosis. Specimens should be collected within 10 days. Testing for mumps specific antibodies (IgM) and IgG seroconversion can be done. To distinguish between wild type mumps and vaccine mumps, an oral or cheek swab is collected and genotyping is performed

Question 11

Treatment of mumps

Answer 11

No specific treatment other than managing symptoms

Question 12

Evidence of immunity to mumps

Answer 12

People must meet one of 4 criteria
1. Documentation of age appropriate vaccination with a live mumps virus containing
2. Laboratory evidence of immunity
3. Laboratory confirmation of disease
4. Born before 1957

Question 13

Care of exposed people

Answer 13

Mumps vaccine has not been demonstrated to be effective in pre-venting infection or decreasing the severity of infection if administered after exposure. However, people without evidence of immunity who are exposed to mumps still should receive MMR vaccine because immunization will provide protection against subsequent exposures

Question 14

Mumps vaccine recommendations

Answer 14

The first dose should be administered routinely to children at 12 through 15 months. The second dose should be administered 4-6 years

Question 15

Can mumps infection be asymptomatic?

Answer 15

Among unvaccinated people, around 20% of infections can be asymptomatic. The frequency of asymptomatic infection among vaccinated people is unknown. Fully vaccinated people can be infected with mumps virus, but are at a much lower risk for mumps illness and its complications

Question 16

How is close contact defined for mumps? (2)

Answer 16

1. having direct contact with a mumps patient’s infectious respiratory secretions by droplet transmission (e.g., kissing,
   sharing saliva-contaminated objects like water bottles, or being coughed or sneezed on). Droplets generally travel ≤3 feet
   when an infected person talks, coughs, or sneezes
2. being in close proximity for a prolonged period of time with a person infected with mumps during their infectious period
   (2 days prior, to 5 days after, onset of parotitis or other salivary gland swelling)

Question 17

Mumps during pregnancy

Answer 17

Mumps infection that occurs in pregnant women is generally benign and not more severe than in women who are not
pregnant. It does not seem to cause issues for the fetus

Question 18

Prevalence of mumps infections prior to the vaccine

Answer 18

The pre-vaccine era was prior to 1967. Mumps was a notable cause of morbidity in the United States, with over 100,000 cases reported each year. During that time, mumps was a universal childhood disease, with highest incidence among children 5–9 years of age. Permanent unilateral deafness occurred in 1 in 20,000 people- bilateral and severe hearing loss was rare. Before 1967, mumps accounted for approximately 10% of all cases of aseptic meningitis.

Question 19

Prevalence of mumps 1967-2005

Answer 19

During this era. there was a reduction in disease. Children received one dose at first, then they began receiving 2 doses in 1989. Following mumps vaccine licensure and ACIP recommendations for its use, reported cases of mumps steadily decreased from
>152,000 cases in 1968 to 2,982 cases in 1985. From 1986-1987, a resurgence occurred due to low vaccination levels among adolescents and young adults. The second recommended dose helped with mumps control

Question 20

Resurgence in mumps cases

Answer 20

There has been an increase in the number of mumps cases since 2006, with most cases occurring in fully vaccinated adolescents and young adults. This was due to outbreaks on college campuses and close knit communities. Cases decreased and began to increase again between 2016 and 2012. Since 2007, patients aged <18 years account for approximately 1/3 of all reported mumps cases, with the majority being vaccinated

Question 21

Mumps vaccine effectiveness

Answer 21

Effectiveness of two doses of the vaccine against clinical mumps disease is 86%. Effectiveness of one dose is 72%. This is lower than for the other two components of the MMR vaccine (97% for measles after two doses and 97% for rubella after one
dose).

Question 22

Factors putting vaccinated people at risk for mumps infection (3)

Answer 22

1. Development of a low immune response (insufficient for protection), decreased immunity (waning) over time after
   initially developing an immune response following vaccination (secondary vaccine failure), or lack of development of an
   immune response after receiving the vaccine (primary vaccine failure)
2. Lower levels of vaccine-induced antibodies against the circulating wild-type virus strains (mainly genotype G in the U.S.)
   compared with the vaccine virus strain (genotype A)
3. During the current period of low disease incidence, lower frequency of subclinical immunologic boosting (re-infection that boosts antibody titers without causing illness) due to lack of exposure to wild type virus

Question 23

Which activities have a higher risk of mumps transmission?

Answer 23

Physical contact, such as attendance at a crowded party, or during dancing, contact sports, kissing or sexual activity and sharing of gym equipment or drinks. Examples of frequent close contact exposures include
prolonged contact such as living in conned or shared spaces, repeated contact such as meeting regularly, or sharing a daily routine.

Question 24

Epidemiologic linkage criteria for mumps (2)

Answer 24

1. Exposure to or contact with a confirmed mumps case
2. Member of a group or population identified by public health authorities as being at increased risk for acquiring mumps because of an outbreak

Question 25

Mumps case notification

Answer 25

Mumps is a reportable condition and must be reported to the state health department within 7 days

Question 26

Mumps pathogenesis

Answer 26

The virus is acquired by respiratory droplet transmission. It replicates in the nasopharynx and regional lymph nodes.
During viremia, the virus spreads to multiple tissues, including the meninges, salivary glands, pancreas, testes, and ovaries. Inflammation in infected tissues leads to characteristic
symptoms of parotitis and other complications such as orchitis
and aseptic meningitis

Question 27

Mumps genotypes

Answer 27

There are 5 different genotypes, type G is seen most often

Question 28

IgM and IgG antibodies

Answer 28

IgM antibodies peak earlier, IgG antibodies peak later and the response lasts for longer