JAMA PEDS: Nasopharyngeal Viral RNA Higher In Young Children Than Adults

Credit Wikipedia

#15,390

If there is one universal takeaway from our COVID-19 pandemic, it is that that early assumptions and  initial impressions regarding an emerging virus are often wrong.  A partial list assumed `facts' about the COVID-19 pandemic virus that have changed significantly over the past 6 months includes:

• SARS-CoV-2 was initially considered primarily a severe pneumonia threat, but now we know it also has an affinity for the cardiovascular system, and can produce neurological manifestations as well. 
• Mild or moderate illnesses - which comprise the majority of infections, were assumed to be self-limiting, and people would fully recover after a week or two.  Today, there is ample evidence that for many, prolonged illness and disability is a genuine concern (MMWR Report).
• Asymptomatic transmission was initially thought to be rare, but has now been shown to be a significant driver of the pandemic (see EID Journal: Asymptomatic or Presymptomatic Transmission Of SARS-CoV-2).
• The notion of `airborne transmission' of the virus (as opposed to large droplet) was dismissed for months but is now, finally, considered at least plausible (see  Study: The Infectious Nature of Patient-Generated SARS-CoV-2 Aerosol).
• The use of masks and face covers by the general public was initially rejected by practically all western nations (and the WHO).  Today, most countries consider it as important as hand washing and social distancing (see The Case For Universal Masking : CDC, MMWR & JAMA).

Naturally, our view of this (or any other) virus evolves over time as new evidence is uncovered.  Many of the early assumptions on COVID-19 were based on what we already knew about influenza, SARS, MERS-COV, and the 4 hCoVs that cause the common `cold'.  

There still remain a number of large gaps in our understanding of SARS-COV-2, and how it spreads in the community.  The impact of ventilation systems and air conditioners remains controversial, as does how much of a factor aerosol transmission is in this pandemic. 

But perhaps the greatest concern, with many schools set to open in a matter of weeks,  is the role children may play in the spread of the virus. 

The vast majority of children appear to experience mild illness - if they are symptomatic at all - although we've seen hundreds of cases of  Multisystem Inflammatory Syndrome in Children (MIS-C) reported in the United States and around the world. 

Recent seroprevalence studies have shown that children and adolescents are infected far more often than previously appreciated - raising concerns that children may be silent spreaders of the virus - and could infect teachers and other school workers, along with bringing the virus home. 

Unknown until now, however, has been whether mildly or moderately ill children shed significant quantities of the virus. 

In an attempt to answer that question, researchers at Ann & Robert H. Lurie Children’s Hospital of Chicago measured the amount of viral load in the noses of 145 mildly to moderately ill COVID-19 patients, ranging in age from under 1 month to over 65 years of age.  

What they found was that children under the age of 5 often had 5 to 10 times more virus in their nasopharynx than older children and adults.  While this doesn't speak directly to transmissibility, it suggests children may be much better spreaders than previously though.

We've two links.  First, to the research letter published yesterday in JAMA Pediatrics, followed by a press release from the Children's Hospital of Chicago.  

Research Letter

July 30, 2020

Age-Related Differences in Nasopharyngeal Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) Levels in Patients With Mild to Moderate Coronavirus Disease 2019 (COVID-19)

Taylor Heald-Sargent, MD, PhD1; William J. Muller, MD, PhD1,2; Xiaotian Zheng, MD, PhD1,2; et al

          (Excerpt)

Our analyses suggest

Thus, young children can potentially be important drivers of SARS-CoV-2 spread in the general population,

          (Continue . . . .)

Young Kids Could Spread COVID-19 As Much As Older Children and Adults

July 30, 2020 

Findings important to nationwide conversations on reopening schools and daycare

A study from Ann & Robert H. Lurie Children’s Hospital of Chicago discovered that children younger than 5 years with mild to moderate COVID-19 have much higher levels of genetic material for the virus in the nose compared to older children and adults. Findings, published in JAMA Pediatrics, point to the possibility that the youngest children transmit the virus as much as other age groups. The ability of younger children to spread COVID-19 may have been under-recognized given the rapid and sustained closure of schools and daycare during the pandemic.

“We found that children under 5 with COVID-19 have a higher viral load than older children and adults, which may suggest greater transmission, as we see with respiratory syncytial virus, also known as RSV,” says lead author Taylor Heald-Sargent, MD, PhD, pediatric infectious diseases specialist at Lurie Children’s and Assistant Professor of Pediatrics at Northwestern University Feinberg School of Medicine. “This has important public health implications, especially during discussions on the safety of reopening schools and daycare.”

Dr. Heald-Sargent and colleagues analyzed 145 cases of mild to moderate COVID-19 illness within the first week of symptom onset. They compared the viral load in three age groups – children younger than 5 years, children 5-17 years and adults 18-65 years.

“Our study was not designed to prove that younger children spread COVID-19 as much as adults, but it is a possibility,” says Dr. Heald-Sargent. “We need to take that into account in efforts to reduce transmission as we continue to learn more about this virus.”

(Continue . . . )

 

These findings fall short of being a slam dunk, as the number of samples collected was relatively small, and they only measured the level of viral RNA - not infectious virus - in the subject's nasopharynx. But their findings are suggestive enough to warrant caution as schools attempt to re-open across the nation next month.  

I fully appreciate the need for scientific evidence upon which to make decisions. And that gathering and analyzing that evidence takes time. 

But as we've waited for answers, we adopted far too cavalier of an attitude about this pandemic - assuming for convenience sake the `best case' scenario whenever possible - instead of considering less sanguine possibilities.   

And so far, that doesn't seem to be working out too well for us.