The investigators’ finding that the youngest children are the most likely to spread the virus in household demands some consideration. Still, there are some surprises in these data.
The Paul et al study now reveals that these measures have served an important purpose as the nation awaited the safety afforded by vaccines. These safety plans were focused on reducing transmission between infected school staff and students, as well as protecting everyone’s family members. 4 But these practices were inconsistent with the available observations that children were both less likely to have severe disease (true) and possibly less likely to spread it to others (not true). In fact, the assumption that infected children were at risk of spreading SARS-CoV-2 was at the core of safety plans in schools and daycares that emphasized the importance of masking and distancing of students throughout the school day. Under these more realistic conditions, we see that not only can infants and toddlers get infected but they can also spread SARS-CoV-2. Times changed and the Paul et al study was conducted as Ontario was getting back to business and Ontario’s children were getting back to school and daycare. Under these circumstances, we were understandably surprised when we diagnosed a young child with COVID. Limited testing capacity, with a focus on testing elderly individuals, health care workers, and those ill enough to require hospitalization, also contributed to the impression that this new virus spared young children. For these households, there were few opportunities for virus to enter the family circle. 3 To understand this apparent contradictory observation, we must remember what happened to infants and toddlers during the early days of the pandemic: they were sequestered, staying at home alongside parents who were working and siblings who were learning remotely. This finding is at odds with early reports suggesting that young children rarely transmit to others. Applying thoughtful stratified and sensitivity analyses, these investigators also developed a more nuanced understanding of how, and potentially why, SARS-CoV-2 spreads more in some households than others.įirst, we learned that while young children (those younger than 4 years) were less likely to be a child primary case, they were more likely to be a source case for other members of their households. Additionally, older children and teens were more likely than toddlers and young children to be the primary household case, consistent with a higher degree of social mobility. The age distribution of most secondary cases indicated that they were likely either siblings (0-20 years of age) or parents (30-50 years of age). Using public health data from the province of Ontario, Canada, investigators identified clusters in which the apparent primary case was a child. With this lens, we read the Paul et al impressive study 2 of the transmission of SARS-CoV-2 virus in households.
While the classic diagram of the “chains of transmission” helps us break down some the factors that determine onward transmission, many respiratory viruses rely on time, proximity, and contact to spread. We can now predict the outcomes-cuddlers were the most likely to get infected. For those who do not recall this study, Hall and Douglas examined the likelihood of transmission from an infant infected with respiratory syncytial virus (RSV) to an adult caretaker who either sat with the infant on their lap, touched the infant while they laid in their crib, or sat next to the crib. With an elegant and simple study design, Hall and Douglas vividly demonstrated that it’s the interactions between susceptible and infected persons that drive much of viral transmission. The iconic article “Cuddlers, Touchers, and Sitters” (formerly entitled “Modes of Transmission of Respiratory Syncytial Virus”) by Hall and Douglas 1 stands to this day as one of the simplest recitations of the behavior of respiratory viruses and children.
0 kommentar(er)
