Nina Panikssery

The hand, foot and mouth disease section is a good example of the review's handling.

It reports that daycare attendance was associated with more severe cases but then immediately offers mitigating interpretation with no evidence.

That prolonged hospital stays might reflect parental work constraints rather than genuine severity.

There's an image here.

Though the review considers severity, it ignores duration.

Their primary metric throughout is episode count.

Also, despite discussing a wide variety of pathogens, it doesn't address which of these infections carry the highest complication rates in infants and toddlers specifically.

Finally, the crucial illness now or illness later is the paper's weakest portion.

It rests on two primary sources for the compensatory immunity claim.

The Tucson Children's Respiratory Study, a cohort study of roughly 1,000 American children followed from birth to age 13 in the early 2000s, finding that daycare attendees had more colds at age 2 but fewer by age 6 to 11.

A Dutch study, Hullergy et al.

2016, of 2,220 children followed for 6 years, finding reduced GI illness between ages 2 to 5 in children with first-year daycare attendance.

Quoting from the study, Quote,

We observed 4,599,993 independent episodes of infection, antimicrobial exposure, during follow-up.

Childcare enrollment transiently increased infection rates.

The younger the child, the greater the increase.

the resulting increased cumulative number of infections associated with earlier age at childcare enrolment was not compensated by lower infection risk later in childhood or adolescence.

End quote.

This is arguably the single most relevant study for the paper's central illness now or illness later question and its three orders of magnitude larger than either study the authors cite.

Its absence is hard to explain.