CD - measles, mpox Flashcards
what is the agent for measles (1)
1- measles morbillivirus
what is the reservoir for measles (1)
1- humans
what is the mode of transmission for measles (2)
1- Airborne, remains in the air with evaporated droplets for at least 2 hours
2- Direct contact with respiratory droplets
what is the incubation period for measles - range (1)
1-
7-21 days
what is the communicable period for measles (1)
1-
4 days before rash onset to 4 days after onset of
rash
what is the basic reproductive number (R0) for measles (1)
1-
R0 = 12-18
what is the secondary attack rate of measles among susceptible persons (1)
1-
90%
what are criteria for immunity re: measles (need to meet any one of these) (3)
1- documentation of vaccination
2- lab evidence of immunity (IgG)
3- history of lab-confirmed measles infection
what are criteria for documentation of ROUTINE vaccination for the following (i.e. how many doses does each group need):
-kids 12mo - 17yo
-adults 18+ born after 1970
-adults before before 1970
(3)
1- kids 12mo - 17yo:
*2 doses
2- adults 18+ born after 1970
*1 dose
3- adults before before 1970
*considered immune from natural infection
what groups of people are considered at greatest risk of exposure to measles - SATH (4)
1- travellers
2- healthcare workers
3- students / shelters (congregate living)
4- adults born between 1970 - 1991 (only received 1 dose)
what are measles vaccination requirements for HCW or military (1)
1-
2 doses regardless of birth year
what are measles vaccination requirements for travellers outside North America (2)
1-
2 doses if born after 1970
2-
1 dose if born before 1970
what are measles vaccination requirements for post-secondary students (2)
1-
2 doses if born after 1970
2-
1 dose if born before 1970 and no documentation of receipt of measles-containing
vaccine
what is the initial clinical presentation of measles F-DICCCK (7)
prodrome of:
1- fever
2- cough
3- coryza (inflammation of mucous membrane in the nose)
4- conjunctivitis
5- drowsiness
6- irritability
7- Koplik’s spots are not always present
how long after being infected with measles virus do initial symptoms tend to appear (1)
1-
7-21 days after being infected (i.e. incubation period)
how long after initial symptoms begin does measles rash appear (1)
1-
3-7 days after other symptoms appear
how long can measles rash last for (1)
1-
4-7 days
what is the physical characteristics of measles rash (1a) how does measles rash generally manifest - where does it start and where does it move to (1b)
1a- generalized erythematous maculopapular rash
1b- begins on the face, advances to the trunk
of the body and then to the arms and legs
what are potential complications of measles infection - BOPPED SDS (9)
1- blindness
2- deafness
3- encephalitis
4- otitis media
5- pneumonia
6- subacute sclerosing panencephalitis
7- premature labour
8- spontaneous abortion
9- death
what tests do you do to diagnose measles and within what timeline can you use each of these tests (3) SNU
Shortest timeline to longest: Serology -> NP -> urine
1- NP/throat swab: within 4-7 days of rash onset
2- Urine PCR: within 14 days of rash onset
3- Serology: IgM antibodies (present 3-4 days after
rash onset) and IgG antibodies
why do you NOT want to test for measles serology, IgM, if onset of rash has been less than 3-4 days (1)
1- IgM for measles can be falsely negative if taken less than 3 days after onset of the rash
what are other febrile rash infections that can cause false positive measles IgM - HEAP (3)
1- parvovirus b19
2- enteroviruses, adenovirus
3- human herpes virus 6 (roseola)
in the travel health context, what are other infections that can cause false positive measles IgM - CZ (2)
1- zika
2- chikungunya
what kind of vaccine is measles vaccine (1)
1- live attenuated
what is the efficacy of measles vaccine (2)
SUMMARY: 2 DOSES OF MEASLES-CONTAINING VACCINE IS NEARLY 100% EFFECTIVE
In general - 94-99% effective:
1- single dose of measles containing vaccine given between 12-15 months is 94-98% effective
2- with second dose (18 months – 4 to 6 years) it is 99% effective
what is the schedule for measles vaccine (2)
1- 2 doses
2- first given at 12 months, second at 18 months (max by 4-6 years)
can measles vaccine be given to children 6 months and older if they are travelling? (1a)
how does this impact their regular measles vaccine schedule (1b)
1a- MMR vaccine can be given to children ≥6 months of age who are traveling internationally
1b- these kids still require 2 regular doses of MMR after 12 months of age
what groups are contraindicated to getting measles vaccine I-PIT (4)
1- pregnant people
2- immunocompromised people
3- infants less than 6 months old
4- active, untreated TB
measles case mgmt: what things do you ask on history as part of case investigation (1a) and why (1b)
1a- TOCIS (travel, occupation, contacts, immunization status, symptom onset)
1b- to determine period of communicability
measles case mgmt: what is management for a case? (1)
1- supportive management
measles case mgmt: who needs to isolate (items 1-6 - CSPWGH) and for how long (item 7)
Isolate from congregate settings, basically:
1- child care settings
2- schools
3- post-secondary educational institutions
4- workplaces
5- sporting events and other group settings
6- healthcare settings
7- isolate for 4 days after the appearance of the rash
measles contact mgmt: what is the definition of a contact (1)
1- any susceptible person who shared the same air space for any length of time during the period of communicability, including two hours after the case left the air space
measles contact mgmt: is there any chemoprophylaxis (1)
1- NO
measles contact mgmt - PEP: what is the general rule regarding measles vaccine’s use in PEP? in relation to time from exposure (1)
1- vaccine is not effective as PEP if it has been >72h since exposure
measles contact mgmt - PEP: what is PEP for infants <6mo (all are susceptible)
*<72h from exposure
*72h - 6d from exposure
(2)
1- IMIg (immunoglobulin)
2- IMIg
measles contact mgmt - PEP: what is PEP for immunocompetent infants 6-12 mo (all are susceptible)
*<72h from exposure
*72h - 6d from exposure
(2)
1- vaccine
2- IMIg
measles contact mgmt - PEP: if immunocompetent infants 6-12 mo receive vaccine as part of PEP, how many additional doses of vaccine are needed for protection (1)
1- Two additional doses of MMR vaccine provided after 12 months of age are required for long-term
protection
measles contact mgmt - PEP: what is PEP for susceptible immunocompetent people >12 mo
*<72h from exposure
*72h - 6d from exposure
(2)
1- vaccine
2- n/a
measles contact mgmt - PEP: why is immunoglobulin not a priority for contacts who are immunocompetent people >12 mo following exposure (1)
1- due to low risk of disease complications - they should only be offered vaccine as PEP
measles contact mgmt - PEP: what is PEP for susceptible pregnant people or immunocompromised people 6mo+
*<72h from exposure
*72h - 6d from exposure
(2)
1- IVIg or IMIg
2- IVIg or IMIg
measles contact mgmt - PEP: why is IVIg used for those weighing >30kg, and IMIg used for those weighing <30kg? (1)
1- if you weigh <30kg (i.e. a child ~6yo and less) then the volume of IVIg that would have to be given to provide protection would be too large (~15mL)
measles contact mgmt - PEP: put another way, which gives you better protection if you weigh >30kg - IVIg or IMIg (1)
1- IVIg
measles contact mgmt: how long should contacts be excluded from childcare/school settings (item 1) and after what criteria have been met (any of items 2-4 - ILI)
and what about children who may only have 1 dose of MMR - how long should they be excluded for (item 5)
1- from days 5-21 post-exposure until:
2- they are adequately immunized OR
3- demonstrate lab confirmation of immunity OR
4- or have received immuneglobulin
5- Susceptible children < 6 years old with only 1 dose of MMR vaccine should be excluded until they receive a 2nd dose of MMR vaccine
measles contact mgmt: how long should HCW with only 1 dose of vaccine be excluded from HC settings (item 1) and after what criteria have been met (items 2-3 - IL)
1- from Days 5 to 21 post-exposure until:
2- they are tested for IgG antibody
3- receive a 2nd dose of MMR vaccine.
measles contact mgmt: do you need to exclude people who have received PEP (item 1) and what is the exception (item 2)
1- No requirement to exclude individuals for any length of time after receipt of vaccine or Ig before their re-entry to childcare facilities, schools, or other settings
2- with the exception of healthcare workers
why is measles a hot topic right now (3)
1- measles outbreaks are increasing in every region globally since 2023, especially 2024
2- also, with the resurgence of global travel, there is higher risk of spread from one region to another
3- COVID pandemic-related gaps in routine immunization coverage, including MMR vaccine, means there are more susceptible kids and thus greater potential for outbreaks
what is the agent for mpox (1)
1- monkeypox virus, which is an orthopoxvirus
what are the clades (subtypes) of mpox (2) and how many sub-subtypes are each divided into
1- clade 1 - divided into 1a, 1b
2- clade 2 - divided into 2a, 2b
what are reservoirs of mpox (1) - M (e.g. DRSG)
1- small mammals from endemic African countries (e.g. dormice, rope squirrel, sun squirrel, Gambian pouched rat)
what is the mode of transmission of mpox - FAVA-D (5)
1- Direct or intimate contact
2- Fomites: Contact with shared, contaminated object
3- vertical
4- Animal-human - animal skin lesion, body fluid,
mucosa
5- ?airborne
what is the communicable period for mpox (2)
1- from onset of symptoms until the scabs have fallen off on their own and the skin is healed.
2- may be contagious up to 4 days before symptom onset
what is the clinical presentation of mpox - some symptoms - PR (mpvpc) FLOP (6)
1- rash: macule -> papule -> vesicle -> pustule -> crusting
2- oral, genital, perianal lesions
3- fever/chills
4- lymphadenopathy
5- pharyngitis
6- proctitis
which clade caused most cases in Canada in 2022 outbreak (1)
1- clade 2b
which clade has been implicated in the 2024 outbreak (not seen in Canada thus far) (1)
1- clade 1b
what are the recommendations surrounding pre-exposure immunization for mpox - what vaccines, how many doses, and who should get it (3)
1- imvamune vaccine
2- get two doses
3- those who are high risk of acquiring mpox
which groups are considered high risk of acquiring mpox - M (1 or more: mphs) WST (4)
1- gbMSM who meet one or more of the following criteria:
* multiple partners
* partner has multiple partners (Are in a relationship where at least one of the partners has other sexual partners)
* history STI (Have had a confirmed sexually transmitted infection acquired in the last year)
* sex-on-premises (Have engaged in sexual contact in sex-on-premises venues)
2- Sex workers
3- Staff or volunteers in sex-on-premises venues where workers may have contact with contaminated fomites potentially
4- Those who engage in sex tourism
what are investigations/diagnostic tests for mpox (items 1, 2 - PV) and where should you collect the specimens from (items 3, 4 - L-norbu)
1- PCR/NAAT (preferred)
2- viral culture
3- skin lesion (fluid, crusts, roofs) - preferred
4- otherwise could use NP, oropharyngeal, rectal, blood, urine
what is the severity of mpox disease (1)
1- can range from mild to disseminated, multi-organ disease
what is the treatment for mpox (2)
1- self-limited, typically
2- TPOXX off-label use (tecovirimat monohydrate capsules - existing treatment for smallpox) for severe or hospitalized cases
what is case management for mpox - CPR-A (4)
1- cover lesions
2- PPE - use PPE when coming in contact
3- reduce contact - have cases reduce contact with vulnerable populations (e.g. immunocompromised, pregnant, children)
4- avoid sexual contact until lesions crusted over
what is contact management for mpox - what is PEP, dosing (and how long after exposure), what to monitor for and do after (4)
1- do PEP with vaccine (Imvamune) to those identified as high risk contacts to confirmed or probable mpox cases
2- first dose given up to 14 days post-exposure
3- monitor for signs and symptoms x 21days from last exposure
4- if symptoms develop - isolate, contact PHU and healthcare provider to start testing
