Most readers of this blog have focused on vaccines for themselves and their elderly relatives: widespread vaccination for children seems a long way off. New data are very clear: children contract and transmit the infection, if anything, more easily than adults. In this post I summarise the recent data from both sides of the Atlantic on the occurrence and severity of Covid-19 in children, and consider the impact of the ‘adult first’ policy on ending the pandemic.
How common is Covid-19 in children?
- It is now widely acknowledged that children are as frequently infected with Covid-19 as adults
- These recent data from a large true random population sample in the UK show that children have slightly higher rates of infection than adults
- Of course, infection rates in any age group are related to the likelihood of being in contact with an infected person, and children are likely via schools to have more social contacts
- One way of investigating this is to compare the risks between children and adults of catching the infection from an infected member in their household
- A recent study did just that and this is what they found:
- As the graph shows, child contacts are just as likely to be infected as adult contacts
What about children transmitting infection to adults?
- A study published last week from Wuhan examined the pattern of transmission in over 57000 households with an infection
- Children, as expected, were much less likely to have symptoms
- They were however 60% more likely to pass on infection than adults aged over 60
- Of course, there are many reasons for this, which might include a reduced level of preventive behaviours (such as social distancing) in young people without symptoms
How severe is Covid-19 in children?
- As is well known children are much less likely to get ill with Covid-19
- But clearly some do get very sick – recent data from the USA showed by end of 2020
- 154 had died
- 7500 had been hospitalised
- In the UK over 2000 children have been admitted to hospital since the start of the second wave in September
- It is also worthwhile making the point that if we had had the same number of admissions to hospital with another viral infection, such as measles, that would be considered a mini public health crisis and trigger a drive to make sure children are protected
What is the story about vaccines in children?
- The 3 currently licensed vaccines did not include children in their clinical trials
- As a result, regulators in both the UK and USA only licensed the vaccines for use in adults, they cannot go beyond the available data
- Regulators have a duty of care and need to be assured of safety – and all medicines, especially those targeted at widespread use, need to provide that assurance
- The immune response to vaccines in childhood and adolescence may not be identical to that in adults and, at the very least, there need to be careful dosage calculations
- It is of interest that both in the USA and in Europe, drug companies have a legal duty to test vaccines in children (but not necessarily at the time of testing in adults)
Why vaccinating children might be important to end the pandemic?
- The vaccines are the way out to end the pandemic and thus far they are successful in reducing the numbers of people getting sick
- As I mentioned in a previous blog, and is mentioned by politicians who are urging caution, the data we currently have do not show that vaccines prevent people contracting the virus and transmitting the infection to others
- In simple terms:
- Person A has been vaccinated
- Person A is then in contact with infected Person B and catches the virus but doesn’t become sick because he has been vaccinated
- Person A can then pass the infection on to others
- This means it is going to be very hard to achieve herd immunity without very high proportions of the population being vaccinated. Protecting adults is not going to be sufficient
- The good news is that this week is that all 3 vaccine companies have started trials, but it may take much longer to get the results than anticipated
- There may also be reluctance to be recruited into a study in which they may end up being vaccinated with a placebo.
- If that worry translates into participants being cautious about social interactions and with schools still being closed, will we get a result that is applicable to the real world?
- All commentators on the pandemic would recommend having the most vulnerable and those responsible for their health and care being a priority for vaccination
- But hopefully the numbers filling our hospitals will decline and the priority will be to protect all of the community
- This underscores the need for clinical trials of vaccines in children, which probably need to be demonstrably even safer than in adults
- We also need research to understand what information parents in particular would require to feel confident to allow their children to be vaccinated – given their admittedly low (but not nil) risk of a serious outcome
- Please feel free to share any comments from your own family!
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