Measles

Question 1

Spread of Measles?

Answer 1

Airborne or droplet

Question 2

Natural course of measles infection?

Answer 2

Prodromal period of 2 - 4 days with fever, coryza, conjunctivitis and cough, followed by mac-pap rash which starts behind the ear and spreads to face a trunk. Generally lasts 3-7 days. Koplik spots can sometimes be seen but are unreliable.

Constellation of conjunctivitis or coryza or cough, rash for 3 days and fever for at least one day are strongly suggestive of measles (according to green book)

Question 3

Complications of measles infections?

Answer 3

• Secondary bacterial infections (typically OM or pneumonia)
• Viral pneumonitis (esp immunocompromised)
• Encephalitis
  – SSPE
  – Post infectious encephalitis
  – Inclusion body (immunocompromised)

Question 4

Effectiveness of one and two doses of MMR?

Answer 4

One dose
- Measles 90%
- Mumps 61-91%
- Rubella c100%

Two doses
- Measles > 95%
- Mumps - >61-91%*
- Rubella c100%

Green book unclear on this

Question 5

What type of vaccine is MMR?

Answer 5

Live attenuated

Question 6

Who gets MMR and when?

Answer 6

Childhood - one dose at 1 year and second dose from 18/12 onwards

Occupational exposure (if not vaccinated as child)

Question 7

Why don’t children <1 year routinely get MMR vaccine and what should happen if they do receive this vaccine?

Answer 7

Concern that maternal antibody will attenuate the response to live vaccine.

If given a dose pre 1 years then they should go on to receive two further doses.

Question 8

How long after immunoglobulins can the MMR vaccine be given?

Answer 8

3 months. Any earlier and the immunoglobulin may attenuate response

Question 9

How do you identify vaccine derived measles infection?

Answer 9

Sample should be sent to Virus Reference Department for either their measles vaccine-specific PCR assay or formal genotyping. ??Genotype A is the vaccine strain which doesn’t circulate (can’t find a reference for this but Emily says from ref lab reports)

Question 10

Incubation period of measles?

Answer 10

10 days (7-21)

Question 11

Infectious period for measles?

Answer 11

4 days before to 4 days after rash onset

Question 12

Measles exposure - definition of group A and actions, if any?

Answer 12

Individuals who should be able to maintain an adequate antibody response from prior infection but unlike pregnant contacts this should be checked by presence of Measles IgG (at any time)

If negative they should get IVIG following a significant exposure.

Question 13

Measles exposure - definition of group B-i and actions, if any?

Answer 13

Individuals who are unlikely to have maintained a immune response from previous immunisation/infection. B-i patients can be managed based on measles IgG following completion of their treatment or at time of exposure.

If negative they should get IVIG following a significant exposure.

Question 14

Measles exposure - definition of group B-ii and actions, if any?

Answer 14

Individuals who are unlikely to have maintained a immune response from previous immunisation/infection. - Individuals who will require IVIG regardless of potential previous immunity.

Question 15

Measles exposure - Who gets IVIG and who gets HNIG?

Answer 15

Group A and B immunocompromised patients get IVIG

Infants and pregnant women (antibody negative) get HNIG

Question 16

Paediatric patient admitted to ward, 24 h later comes out with rash, PCR positive for measles, unvaccinated. What prophylaxis:

A 5 m old sibling, mum 2x MMR

B 1 y in 4 bedded bay with bronchiolitis

C 24 y nurse 18 weeks pregnant, 1 dose MMR, IgG equivocal

D 11 y on infliximab, IgG pos pre-treatment.

E Uncle 3 m post BMT, 2x MMR pre BMT. Face to face 4 days prior to symptom onset

Answer 16

Infection period for measles 4 days before to 4 days after rash.

A - Sibling - HNIG within 72h ideally, Mum - none

B - MMR vaccine (incl 2nd dose at 18 months onwards)

C - Equivocal in pregnant women has been shown to equate to good measles neutralisation so are actually immune. Not considered for IVIG.

D -Manage on the basis of IgG at the time of exposure (Group B1)

E -VZIG (group B2) (assuming symptoms onset means rash onset and not coryza. If not unlikely to be in infectious period as prodrome exists for a few days before rash and infectivity = rash +- 4 days.)

Question 17

Patient comes to GP with 10 month old asking for early MMR due to outbreak in community

Answer 17

Offer MMR but will require 2 further doses after 1 year of life.

Question 18

Renal tx patient measles IgG neg, inadvertently given 1x MMR.

Answer 18

Inadvertent administration of MMR should be treated as potential exposure and managed as per guidelines. (NB this doesn’t apply to pregnant women).

This patient falls into group Bi - should have immunity checked following rx/at time of exposure, so urgent measles IgG + IVIG if neg.

Question 19

Who falls into group A contacts?

Answer 19

Group A. Individuals who should develop and maintain adequate antibody from past exposure or vaccination Manage on basis of evidence of protection at any time (prior to or since the diagnosis or treatment end):

Patients receiving or within 6 months of completing immunosuppressive chemotherapy or radiotherapy for malignant disease (other than those with all, a lymphoproliferative disorder or who have had haematopoietic stem cell transplantation, HSCT).

Patients with human immunodeficiency virus (HIV) infection: i) over 5 years of age and with a CD4 count less than 200 cells/μl (but without a diagnosis of AIDS) or ii) aged 5 years or less, with a CD4 count less than 500 cells/μl
Patients with chronic immune mediated inflammatory disease who are receiving or have received immunosuppressive therapy:
* moderate to high dose corticosteroids (equivalent ≥20mg prednisolone per day; children one mg/kg/day) for more than 10 days in the previous month
* long term moderate dose corticosteroids (equivalent to ≥10mg prednisolone per day or children 0.5 mg/kg/day for more than 4 weeks) in the previous 3 months
* adults on non-biological oral immune modulating drugs, for example, methotrexate >20mg per week (oral and subcutaneous), azathioprine >3.0mg/kg/day; 6mercaptopurine >1.5mg/kg/day, mycophenolate >1g/day, in the previous 3 months
* children on any dose of non-biological oral immune modulating drugs
* certain combination therapies at individual doses lower than stated above, including those on ≥7.5mg prednisolone per day in combination with other immunosuppressants (other than hydroxychloroquine or sulfasalazine) and those receiving methotrexate (any dose) with leflunomide in the previous 3 months

Individuals who have received a short course of high dose steroids (equivalent >40mg prednisolone per day or children 2 mg/kg/day for more than a week) for any reason in the previous month.

Question 20

Who falls into group Bi for contacts?

Answer 20

Manage on basis of IgG obtained at the time of exposure (or since the diagnosis or treatment end):
* patients on or after completion of immunosuppressive chemotherapy for acute lymphoblastic leukaemia (all)
* patients with lymphoproliferative disorders (including haematological malignancies such as indolent lymphoma, leukaemia and plasma cell lymphoma)
* patients who have received a solid organ transplant
* patients more than 12 months after receiving a haematopoietic stem cell transplant (HSCT) patients receiving or within 6 months of completing biological therapies (alone or in combination with steroids); these include:

o monoclonal antibodies, for example, alemtuzumab,
o fatumumab
o rituximab cytokine inhibitors, for example, etanercept

• patients with a diagnosis of acquired immunodeficiency syndrome (AIDs)

Question 21

Who falls into Group Bii for contacts?

Answer 21

Offer PEP regardless of status:
* patients who have received a haematopoietic stem cell transplant (HSCT) within the past 12 months
* patients with persistent agammglobulinaemia (IgG less than 3g/L) due to primary immunodeficiency (for example, common variable immunodeficiency) or secondary to disease or therapy (this group may already be on long term IVIG replacement, which should provide equivalent protection to post exposure immunoglobulin)

Question 22

MMR/Vaccine for pre 1 year old children. ?Age cutoffs?

Answer 22

Infants under 6 months
- Assume susceptible and administer HNIG, ideally within 72 hours but up to 6 days, regardless of maternal status.

Infants aged 6 to 8 months
- For household exposure, administer HNIG, ideally within 72 hours but up to 6 days if necessary.
- For exposures outside of the household, administer MMR, ideally within 72 hours.

Infants 9 months and older
- Administer MMR vaccine, ideally within 72 hours of exposure.

Vaccines given pre 1 year should be followed by full course after 1 year

Question 23

Definition of and how to test for breakthrough measles?

Answer 23

The term ‘breakthrough measles’ (previously referred to as ‘reinfection’, or secondary vaccine failure) is used to describe a confirmed case of measles in someone who developed immunity to
measles, either from natural measles or from prior receipt of measles containing vaccine, typically between 6 and 30 years after infection or immunisation

Breakthrough measles can be confirmed by detection of high avidity measles IgG in serum or high levels of measles specific IgG in oral fluid. Measles IgM in serum may be negative.