It's often the case that respiratory viruses peak in children during the winter - with kids barely recovering in between episodes of coughs, colds and fevers.
But one doctor says parents are questioning this more than ever after an increase in what feels like endless bouts of illness.
With so much concern around it right now, paediatrician Alasdair Munro has attempted to reassure anxious mums and dads about what the norm is for kids getting sick.
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He says it's 'completely normal for young children to suffer from a surprisingly large number of respiratory tract infections' as their immune systems are still developing.
And because of Covid, with little social mixing, it's only now that many children are being exposed to viruses.
He said: "Things seem particularly bad at the moment for several reasons. Winter is always a time where more of these viruses circulate, but this winter is particularly bad.
"For a long period during the pandemic, many of these viruses stopped circulating altogether. Because so few people were catching them, there is less immunity among children - and indeed adults - then there would normally be, so more people are catching them now, including more children are catching them for the first time.
"For the age group particularly prone to these viruses - children under five years - most or all of their lives has been lived during the pandemic period where substantially lower rates of these viruses have been circulating. A lot of first exposures which might have otherwise happened over a few years are now happening within a much shorter timeframe."
Writing in The Munro Report, a newsletter with analysis on issues affecting science, medical research, child health and infectious diseases, Alasdair says frequent, benign viral upper respiratory tract infections in infancy are not usually a cause for concern.
It's only when there are signs of underlying problems with the immune system, with unusually severe infections and frequently requiring hospitalisation, that would prompt further investigation.
"It is normal for young children to have lots and lots of viral respiratory infections," he said. "There are currently more viruses circulating than usual as young children have been relatively unexposed during the pandemic period and are encountering many of them for the first time.
"We are rarely concerned about children suffering frequent viral respiratory infections which follow the normal course. We become concerned when infections are unusually severe or involve opportunistic organisms which would not normally cause infection in people with functioning immune systems."
Just this week, Alasdair, a senior clinical research fellow in paediatric infectious diseases, has been 'busting the bizarre myth which emerged online that Covid-19 causes immunodeficiency in kids' - a myth he says is 'fuelled by serious overinterpretation of basic research and simple misunderstanding of clinical findings'.
"What may be true of Covid-19 - and is certainly true of many respiratory viruses - is that during the acute infection and a brief period afterwards you may be more vulnerable to infections with bacteria; so called superinfections. But this phenomenon ‘does not an immunodeficiency make’," says his latest report, written in collaboration with Dr Andrew Croxford.
"Covid-19 can cause transient alterations to the immune system during and shortly after acute infection which is consistent with other respiratory viruses," it adds.
"There is no evidence Covid-19 cause any long term immunodeficiency. There is no evidence Covid-19 infections have had a meaningful impact on unseasonal or unusual surges in other infections, which were largely predicted as a result of suppressed transmission during the pandemic."
Read more from Alasdair and subscribe to The Munro Report on his website.
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