RSV Flashcards
What type of vaccine is new RSV vaccine?
mRNA vaccine
Which trial showed benefit of a new monoclonal nirsevimab
MELODY/ HARMONIE trials
licensed MHRA November 2022
B cell generation
How effective is new RSV vaccine?
two vaccines exist
67% and 94% effective against RSV A/B
What is target of RSV vaccine?
mRNA vaccine
directed against pre-F protein
Does PCR testing detect both RSV A/B?
Yes
They share 81% nucleotide identity
1 serotype of RSV (when serology testing was done)
Which has two Types:
A - 23 genotypes
B - 6 genotypes
What are the important proteins/glycoproteins of RSV?
G glycoprotein - attachment protein to ICAM-1
F glycoprotein - fusion glycoprotein
M protein - matrix protein. Organsises virion components ready for budding
What does G glycoprotein bind to?
What does F glycoprotein bind to?
G-glycoprotein - binds to host cell surface adhesion molecules
F glycoprotein - ICAM-1 which stimulates fusion
How does RSV evade immune system?
Inhibits IFN alpha production
Inhibits TNFalpha production
Inhibits cell apoptosis
Who is eligible for RSV vaccine?
Pregnant women
Age >60
Vaccine currently not licensed for use in infants
Infants will benefit from maternal vaccine. High risk will benefit from nirsevimab
What was name of trial of RSV vaccine in pregnant women?
MATISSE study
outcome - medically attended RSV visits - e.g GP/ hospitalisation
70-80% effective
What is mechanism of action of nirsevimab?
binds to RSV pre-F glycoprotein - prevent fusion
reduces medically attended hospitalisation/ GP by 80%
Child with wheeze
What viruses should be test for?
RSV
Human Parainfluenza (particularly HPIV3)
Adenovirus
Influenza
Covid
Seasonal coronavirus
Rhinovirus
Mycoplasma pneumonia
Bordetella pertussis
What are benefits of mRNA vaccine technology?
Can change mRNA sequence quicker in response to mutations
eliminate need for purification step - that is required by protein/ subunit vaccines
prevent anti-vector immune response e.g like those seen in adenovirus vector vaccines
mRNA vaccine has strong humoural and cellular immunogencity
What drugs can be used to treat RSV infection?
Include new drugs
Ribavirin - IV or nebulised
Newer drugs:
Fusion inhibitor
Presatovir/ Ziresovir - prevent f-protein cell-cell fusion
Nucleoside analogue
Lumicitabine - block viral transcription and replication
Why is ribavirin not used commonly?
Teratogenicity in pregnancy
Bone marrow suppression - haemolytic anaemia
