RSV Vaccines (Teng - 9/20/23)

 A recording of this presentation can be viewed HERE.

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Many thanks to Dr. Angelica Teng for a breaking-news Grand Rounds presentation on the brand new RSV vaccines that are rolling out just in time for the 2023-24 RSV season. A recording  of her presentation is available at the link above. 

My written notes below:

RSV, as you may already know, is an RNA virus that infects the lungs and leads to lower respiratory tract infections (LRTIs). It is the most common cause of LRTIs in infants and toddlers, leading to 2.1 million clinic visits per year in children <5 years old. RSV has less impact on adults, but does lead to 60-160K hospitalizations per year in adults >65.

Here is the link to an excellent video demonstrating classic findings in RSV bronchiolitis: https://www.youtube.com/watch?v=oOrty5PfhTY

RSV tends to be seasonal, with a typical RSV illnesses  starting in early fall (usually November in CA), peaking in winter (February), and then tapering off in early spring. It spreads mostly via droplets (cough) and can live up to six hours on hard surfaces

source: CDC

Here is the good news!

There are THREE new RSV vaccines approved in 2023

Abrysvo 

Arexvy

Nirsevimab 

There are THREE groups of patients we should consider for the new RSV vaccinations

1) Adults over 60 (Abrysvo or Arexvy)

2) Infants <8 months (Nirsevimab)

3) Pregnant women between 32-36 weeks EGA (Abrysvo)

Adults > 60: Abrysvo and Arexvy are recombinant vaccinations, each made slightly differently with inactivated proteins. Both were FDA approved in May 2023 for adults over 60. In RCTs, both vaccines were found to reduce the risk of RSV-lower respiratory tract infection by 82-89% in older adults in the first year after receiving the vaccine.  They are similar to one another, except for the inclusion of an adjuvant in Abrysvo formulation.

Infants < 8 months: In July 2023, the FDA approved a new monoclonal antibody called Nirsevimab for infants ages 1 week to 8 months during RSV season. Monoclonal antibody therapy is not technically a vaccine but can provide an infusion of prefabricated antibodies, giving temporary protection for up to five months to newly developing pediatric immune systems. In a clinical trial, nirsevimab was ~77% effective against both hospitalizations and cases of RSV requiring a doctor’s visit. The CDC is  recommending that all infants <8 months during RSV season  receive Nirsevimab and additionally children ages 8-24 months with high risk conditions (e.g. prematurity, congenital heart disease, cystic fibrosis, neuromuscular disorders).

Pregnant patients 32-36 weeks: Finally, in August of 2023, the FDA approved Abrysvo as the first-ever maternal vaccine intended to help protect newborns against RSV. It was studied in late third trimester (32-36 week EGA) with the idea that protective IgG from the RSV vaccine moves across the placenta and grant protection for newborn infants.  The vaccine was found to be 82% effective at protecting infants from severe illness during the three months after birth and waned to 69% effective over six months during a double-blind study. Of note, ACOG has not yet put out a formal statement about this vaccine. This is expected by late October.

A few key notes to consider:

1) Unlike a more traditional age-based recommendation for vaccination in adults >60, the CDC recommends for Abrexvy and Abrysvo that the decision to vaccinate be a shared decision between the physician and the patient. Consideration should be based on risk, and certain conditions are associated with higher risk of severe disease (e.g. lung disease, renal disease, nursing home and long term care facility residency). 

2) The RSV for pregnant woman is in no way intended to protect the mom from RSV infection and complications. It is purely meant for the infant.

3) There was a non-statistically significant outcome of low birth weight in women who received vaccination in the third trimester.

4) While there is no official statement, it is believed that guidelines will ultimately recommend that parents choose between the maternal vaccine at 32-36 weeks and the nirsevimab for infants. There is no current belief that children will need both. But this could change.

5) The only absolute contraindication to vaccination with Abrexvy or Abrysvo is anaphylaxis to any of its components.

6) It is okay to administer the RSV vaccine at the same time as either the flu or the COVID vaccine (local recommendation is to do 2 but not all 3 at the same time)

7) It is okay to administer the RSV vaccine when someone has mild cold symptoms

8) The monoclonal antibody nirsevimab is though to have a 5 month protective duration

9) It is unclear when/whether nirsevimab will replace palivizumab (synagis), the old very expensive monthly monoclonal ab that is currently used to treat high risk preemie babies during RSV season. It is likely that a single dose of nirsevimab will be more cost effective.

summary chart, source: A Teng