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Abstract

This paper presents three hypotheses on the pathogenic transmission between schools and homes with a focus on COVID transmission; however, this will show how this applies to any pathogen with a reproductive number (R0) greater than 1 (R0 > 1).  Children and young adults are often asymptomatic while very contagious, and inadvertently become the silent catalyst to exponential growth while schools are open. 

Introduction

It is widely understood that when schools are in session, children come home with more coughs, runny noses, headaches, sore throats, and other symptoms because they were infected with some virus by another student.  By the same token, COVID may be spread within schools, and then from schools to homes.

SARS-CoV-2 is spread via aerosolized respiratory droplets exhaled with every breath of an infectious person.  It is estimated that each person will transmit the virus to between 3 and 10 other people.  In a classroom setting, teachers and students are in the same room for hours at a time. Similarly, when children go home from school, they are with their parents and siblings for hours.

Looking at transmission in the United States has been difficult because every state, county, and school district has operated under different mitigation policies. To get a better understanding of how mitigation policies helped, we can get a clearer picture by tracking countries that were implementing national guidelines for schools.  Some countries opened and closed schools on a consistent national school calendar, and enacted policies on a national level when transmission became too high. By eliminating local inconsistencies such as those found in the United States, we are able to attain a clearer picture of what impact different policies are having on transmission.

An efficient path of transmission that has been overlooked by the CDC, public health, healthcare and most researchers around the world is between schools and homes. This study explores how the virus uses children’s movement between schools and homes to gain exponential growth.

I. Transmission

The Reproductive Number for COVID 

The Reproductive number R0 estimates the speed at which an infectious disease will spread through the population. For R0 > 1, exponential growth will occur because each person is transmitting the virus to more than one other person. When R0 < 1, the transmission is not going to continue expanding because each person is transmitting to less than one person. The higher the R0, the faster the virus will spread through the population. For comparison, here are the reproductive numbers for recent COVID variants, as well as some well-known infectious diseases with high values of R0.

1918 Influenza –          1.4-2.8                                   2009 Influenza – 1.4-.1.6

SARS –                            0.19-1.08                              Chickenpox –    10-12

Common Cold –            2-3                                          HIV/AIDS –      2-5

Seasonal Influenza –      0.9-2.1                                 MERS –             0.3-0.8

Ebola –                              1.56-1.9                                EBV-                 1.2

BA.5 - 6

●   The original SARs-COV-2 first found in Wuhan, China had an R0 of 1.5 to 3.5.  The Delta variant had an R0 of 5.08. The Omicron variant (BA.1) had an R0 of 8.2, and BA.2 has an R0 of 12 - 14.  The latest evolutionary jump is CH.1.1 which is in 24  U.S. States and 36 countries will likely represent the majority of U.S. infections in the near future.  CH..1.1 has a logistical growth rate of 9.90 compared to 

BA.2.  Immune Escape is 0.907 Mutational Fitness: 3.33

II. Hypothesis and Evidence

Pathogenic Exponential Growth Between Schools and Homes 

School calendars, climates, and cultures vary around the world.  It appears that COVID transmission increases and decreases with school openings and closings regardless of climate, culture, or school calendar.  

Viral Loads in Asymptomatic Children 

Previous work indicates that asymptomatic children infected with COVID have higher viral loads, for longer durations than symptomatic individuals.  

A 2021 study showed that asymptomatic patients have higher viral loads than symptomatic patients and a significant decrease in the viral load of nasopharyngeal/oropharyngeal samples with increasing disease severity. (Chapell, 2022) Another study suggested that “younger children may be more likely to transmit SARS-CoV-2 infection compared with older children, and the highest odds of transmission was observed for children aged 0 to 3 years." (Paul, 2021)A previous study looked into the duration of children were infectious. It showed that children aged 6 to 15 years old remained contagious for up to 19.5 days, a little longer than the 16 to 22-year-old group (18 days). If asymptomatic children have higher viral loads for a longer duration than adults, then we can see how classrooms become places of transmission and how that transmission could happen without anyone being aware of it. (Davies, 2020) 

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Transmission in a Contained Environment

A COVID outbreak aboard a cruise ship provides some insight. “An expedition cruise ship departed from Ushuaia, Argentina, for a planned 21-day cruise of the Antarctic Peninsula, including Elephant Island, before sailing to South Georgia Island on a route similar to that taken by the British explorer, Ernest Shackleton, in 1915–1917. The ship departed in mid-March 2020 after the global COVID-19 pandemic was declared by the WHO, with all 128 passengers and 95 crew screened for COVID-19 symptoms, and body temperatures were taken before boarding. “ (Ing,2020) Of the 217 passengers and crew on board, 128 (59%) tested positive for COVID-19. They were quarantined after the first passenger tested positive. Of these, 80% were asymptomatic, but this was the original strain of the virus. The variants today similarly cause 80% of adults to be symptomatic, however, “51%-70% of all verified infected children are asymptomatic. Asymptomatic children constitute a reservoir for infection among children and for the entire population.” (Burak,2020) The variants circulating in May 2022 are five times more contagious. On the cruise ship 59% of people were infected within the first 4 days, then remained in their cabins even for meals. In a typical classroom, children are closely spaced classrooms for 6 to 8 hours a day with variants that are 5x more contagious. The BA.2 and BA.2.12.1 variants bypass antibodies and partially evade T-cell response, and most children are currently attending school without any mitigating protections. 

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