Vaccinating children: arguments for and against

One of the tragic aspects of the news about the escalating pandemic in India is the relatively high proportion of children and young people, not just in the number of cases overall, but also – unexpectedly given Western experience – amongst those with serious infection.  This raises the issue as to the possibility of children being more vulnerable to new variants  and hence whether Western countries need to give greater attention to vaccinating children.  In this post I consider the most recent information and indeed expert opinion on this issue.

Size of the Covid-19 health burden in children 

  • That children also develop Covid-19 in large numbers is not debated
  • The rate of childhood infections is to a great extent related to social mixing at schools and similar institutions 
  • Probably, given exposure to a similar level of the source, children become infected at the same rate as adults
  • Our safeguard from becoming seriously ill with an infection depends on the effectiveness of the ‘first strike immune system’ (referred to as the ‘innate’ immunity we all have in the lining of our noses and throats that protects us against invading bacteria and viruses)
  • Research published this month showed that the innate system is stronger in children and this might explain the lower risk 

Serious infection in children

  • Despite the above, children can still become seriously ill
  • There have, for example, been over 250 child deaths from Covid-19 in the USA
  • The latest data show that 3% of all cases of Covid-19 hospitalised in the USA are in children 
  • It is also established that some groups of children are at particular risk of having bad infection and dying
  • The other health concern is the very strange and rare disorder called ‘multisystem inflammatory syndrome in children’ (MIS-C)
  • Indeed, there have been 3000 cases of MIS-C up to April this year in the USA
  • This severe and previously much less known disorder is difficult to treat and possibly 70% require admission to intensive care, although with adequate treatment mortality rate is only around 2%

What is the state of vaccine testing in  children? 

  • Given concerns about the potential hazard of cerebral venous thrombosis from the AstraZeneca vaccine, this is not I believe being tested further in children 
  • Currently vaccines from Moderna and Johnson & Johnson are being tested and results awaited
  • Data have been published from Pfizer 
    • 2000 adolescents aged 12-15 involved in clinical trial
    • 18 cases of infection occurred in those that had placebo
    • No cases of infection in those who had the active vaccine
    • There were no serious reports of side effects
  • Pfizer want the authorities to license the vaccine for this age group and the result of this application is awaited
  • But  the trial was not large enough, nor could it easily be so, to confirm the necessary safety from serious but uncommon side effects
  • Similarly, given that the cases in the placebo arm were mild or asymptomatic, we do not know how many thousands of children would need to be vaccinated to prevent one serious infection

The ethical arguments for and against vaccinating children

  • One powerful argument in favour is that even the relatively small number of Covid-19 deaths and cases of MIS-C still represents a substantial public health problem
    • Measles vaccine was introduced in the USA at a time when there were 300 deaths a year in children – not too dissimilar from Covid-19 
  • As shown above, there are certain especially disadvantaged groups of children at high risk 
  • In addition, child death rates from Covid-19 are higher in those from certain minority groups – representing an equality issue
  • High vaccine uptake will help ensure full time schooling is more likely and “sellable” to parents
  • The two main arguments against are (i) the low actual risk from the virus, and (ii) the potential of harm from the vaccine
  • Ethically speaking, in  a world where there are vaccine shortages in low-income countries, is there not a responsibility to give vaccines as a priority to adults in those countries?

Herd immunity

  • The main epidemiological question is whether vaccinating children increases the likelihood of herd immunity reducing the risk of infection in adults
  • This raises the ethical question as to  the acceptability of widespread childhood vaccination which is mainly aimed to protects adults – whether or not children will benefit themselves 
  • Put simply – “will the virus disappear more quickly if children are vaccinated?” or indeed the converse “will the virus still be around if we don’t vaccinate children?”, as outlined in a recent New York Times leader
  • There is no proof of this however
  • Indeed, data from Israel would seem (thus far) to suggest that herd immunity – as exemplified by the number of new cases dwindling to almost none – might be accomplished without vaccinating children 
  • A related biological argument is that if children are not vaccinated, is there a risk that new variants will arise in children that will then spread to vaccinated adults, whose vaccine status is not sufficient to protect them against such variants 
    • Whilst such an argument is superficially persuasive, there are no data (as yet) to support it
    • Many expert virologists have struggled to find evidence that this has happened with other viral infections and vaccines 
  • The second question which is the converse of the above is whether we don’t need to vaccinate children as they benefit from the herd immunity provided from high rates of vaccinated adults 
  • Data (also from Israel) this month would support this: population surveillance of new cases suggest that the increasing rates of vaccination in adults have seen a parallel reduction in cases of infection both in adults and in children 
  • In other words the lower rates of infection in children may be explained by the protection from high rates of vaccine uptake in adults
    • But it is only recently that lockdown has been relaxed in Israel  and children have returned to school – so if there had been a surge, it would not have been picked up by this research study
  • Similar data from the USA have shown that a reduction in the number of cases in adults, which is thought to be partially explained by vaccine uptake in adults, is also mirrored by a similar reduction of cases in children 

And my conclusion?

  • This is really difficult, for the reasons I have stated 
  • So, it is not surprising there is not a clear cut conclusion to be drawn at this stage
  • The vaccines are probably as safe as is reasonable, so that supports childhood vaccines
  • Children may indeed be protected by high rates of vaccination in adults 
  • It is much less obvious that high rates of vaccination in children will protect adults 

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