Thread by @pwhickey

A lot of tweeting about what the proper infection control method for RSV is.
I’ll tell you the text book answer and then speak a little bit to how we got there…
🧵

While some hospitals may have stricter requirements, standard precautions (hand washing) plus contact precautions (gown and glove) is the recommendation. This extract from the AAP’s Committee on Infectious Diseases - the Redbook, reflects the standard of care.

I’m curious how we got to this recommendation and whether it stands up to current knowledge (or lack there of). RSV was recognized as a major problem for infants - including the risk of nosocomial transmission in the 70s.

This 1973 paper from England, by Dr Gardner and colleagues provides a detailed account of nosocomial transmission of various respiratory viruses, including RSV. Their focus is largely on ward design and the effect of mixed cohorting of beds. ncbi.nlm.nih.gov/pmc/articles/P…

This 1975 paper by Dr Caroline Breese Hall and colleagues is the earliest papers I could find focused on RSV (working off my phone on a Sunday morning 🤷‍♂️).

It found…

nejm.org/doi/10.1056/NE…

“45 per cent of infants hospitalized for one week or more became infected, and the percentage increased with length of stay. Ten of 24 staff members also acquired the virus and appeared to play a major role as virus carriers”

Dr Hall would go on to write many more papers on this topic, and start to systematically address the topic of prevention strategies inside the hospital.

This 1978 paper discusses efforts to prevent nosocomial transmission & highlights the need for a solution: “Studies a year previously had revealed that 45% of contact infants & 42% of the staff had acquired nosocomial RSV infections.”

What did they do?

pubmed.ncbi.nlm.nih.gov/724317/

“Methods included isolation and cohorting of infected infants, strict handwashing, use of gowns, & the cohorting of staff to the ill infants.”

Why aren’t masks discussed? 🤷‍♂️

Certainly anyone caring for infants with RSV can speak to the thick & copious sections that can occur…

123 infants studied
36 admitted with RSV
87 “contact infants”
8 (19%) acquired nosocomial RSV disease
3 developed pneumonia 1 died 💔

43 staff members
24 (56%) infected
82% symptomatic.
4 had repeated infections within weeks of the initial infection 👀

Conclusion:
“The employed procedures appeared to have decreased the transmission of RSV to infants but not to the staff. Staff may continue to be infected by large droplets from close contact with ill infants or by self-inoculation of contaminated secretions.”

Flash forward to 1982 and Dr Hall is writing review papers on this topic. She notes, “all of us are potentially susceptible to RSV re- infection despite our possession of measurable amounts of serum antibody. Immunity to RSV remains a conundrum.”

ncbi.nlm.nih.gov/pmc/articles/P…

On nosocomial prevention “hand washing has been emphasized and gowns worn whenever direct patient contact occurs. The number of patient contacts and visitors to the ward have also been limited.” What did that yield?

“Such techniques have resulted in a diminished number of nosocomial infections in infants, but appear to have no effect on the rate of nosocomial infections in exposed personnel”

This is a good example of how we can reduce risk to other patients

We also know it is persistent on surfaces hence the emphasis on cleaning

In this case, medical staff may have acted as fomites between patients.

Yet contact precautions alone were not enough to protect staff.

Dr Hall notes, “Theoretically three modes of viral transmission are possible
(1) by small particle aerosols,which could travel appreciable distances (greater than 6 feet)…

(2) by large-particle aerosols or droplets,which can travel only short distances and, therefore, whose spread would require close contact, or (3) by fomites and inoculation from contaminated hands.“

Does this internal debate sound familiar?

I read these articles and I’m really wondering if I’m missing some baseline assumption that contemporary readers would have had that staff were ALSO wearing masks as a routine matter for patients with respiratory illnesses- but I don’t think I am.

Dr Hall presents a great overview of how RSV survives in the environment on hard surfaces- serving as a an opportunity for occult contact transmission.

She also highlights a study where different cohorts of staff using different protective measures and having different behaviors (“cuddlers, touchers, and sitters”)
pubmed.ncbi.nlm.nih.gov/7252646/

Dr Hall’s conclusion- “RSV may be spread by close contact with direct inoculation of large-particle aerosols or by self-inoculation after touching contaminated surfaces. However, spread by small-particle aerosols does not seem to be a major mode of transmission.”

Knowing this, it’s interesting that preventing the “primary” route has won out over the totality of how to prevent nosocomial infections- I suppose people chaffed at wearing masks even then.

An early mentor of mine, Dr James Bass always encouraged us to keep our old Redbooks so we could understand how things change - or don’t over time. Maybe I need to start scavenging those from before I practiced…

It’s probably (past) time for me to go do my yard work so please add to this if you know about the history of how this knowledge was applied (or not) to the Redbook over time. I’ll leave with a quote from Dr Hall:

“RSV Is only about 25 years old in terms of recognized birthdays. Yet during this period it has been demonstrated to be an ubiquitous and highly contagious virus of pathogenic import…

Transmission of RSV appears to require close contact. Inoculation occurs primarily through the eye or nose directly by large particle aerosols or in directly after touching contaminated surfaces.”

End

*or the patients completely

Adding this recent editorial that one of my fantastic PEDs ID colleagues @Lakshmi_RKG pointed me to academic.oup.com/jid/article/22…

A memorial manuscript about Dr Hall

https://twitter.com/pwhickey/status/1584327062319665152