Children and teenagers have been spared the worst of the Covid-19 pandemic, in medical terms at least, even though it has affected them in many other ways.
They are less likely to test positive for the virus and, if they do, are much less likely than adults to become seriously ill. Estimations of just how much they can transmit the virus have fluctuated, especially with new variants, but it is still believed they spread it less than older people.
Up to May 11th, 8,309 children aged 0-4 had tested positive for the virus, of which 187 were hospitalised, according to figures from the Health Protection Surveillance Centre. In the 5-14 age group, there were 18,782 cases, of which 152 were admitted to hospital. The next age cohort for recorded cases spans 15-24 and there the total rises to 44,551, of which 575 spent at least one night in hospital.
For the overwhelming majority of children, Covid-19 is a mild illness, says Dr Ronan Leahy, consultant in paediatric immunology and infectious diseases, at CHI at Crumlin. International studies indicate that only about 2-3 per cent of children infected are hospitalised; of those who are admitted, about one in five goes to intensive care and one in 10 needs to be ventilated. The paediatric hospitals are seeing similar trends here.
“When the virus appeared first, we were very anxious that it would affect those of our children who have underlying problems, such as cystic fibrosis, congenital heart disease, those with immune deficiencies and those being treated for cancer,” says Leahy. But these vulnerable children haven’t become ill in the way that was feared initially.
“We have only had a very small number of children with underlying problems who have got quite sick from Covid,” he says.
There are a few theories why children are getting less sick with the virus, he explains. One is that their younger immune systems are nimbler. Secondly, because younger children are probably exposed to other forms of coronavirus more regularly, they are likely to have some element of “cross protection” from those.
“The third hypothesis is that the virus accesses your cells using the Ace2 receptor and we believe there are fewer Ace2 receptors of respiratory cells in children as there are in adults, so it’s possible the virus cannot access these cells as effectively as it does in adults.”
However, even if most children and teenagers don’t become very ill with the virus, a few do; it can also disrupt their lives through lingering effects or through the need to isolate, even if just a close contact of an infected peer. And, of course, they may transmit the virus to a more vulnerable person.
For those reasons, going on to vaccinate younger teenagers and children after the current schedule is completed may prove to be an essential step for long-term living with the virus.
Are Covid-19 vaccines on the way for teenagers and children in Ireland?
The Pfizer/BioNTech vaccine is already approved for those aged 16 and upwards, and is being used from that age here in the very high-risk and high-risk categories of people aged 16-69 who have been prioritised for immunisation. The current planned rollout of vaccinations works its way down to age 16.
The other vaccines currently authorised for use within the European Union – the Moderna, the AstraZeneca and one-shot Johnson & Johnson – only have EMA approval from age 18 upwards – although the latter two, due to associations with a very rare side effect of blooding clotting disorder among younger people, is recommended here for use only in over-50s where possible.
At the beginning of May, the European Medicines Agency (EMA), started to evaluate an application from Pfizer to extend the use of its vaccine to those aged 12-15, and is expected to issue its recommendations early in June. Canada became the first country in the world at the start of May to approve its use for 12 years and up and was followed by the United States a week later.
What happens if the EMA approves it?
The EMA’s opinion will be forwarded to the European Commission, which will issue a final, legally binding decision applicable in all EU member states.
"Ireland participates fully in this process through our Health Products Regulatory Authority," says a spokeswoman for the Department of Health. The National Immunisation Advisory Committee will examine the EMA findings and advise the Government on how the vaccine might be used here for those aged 12-15.
How’s that likely to play out?
It’s too early to second-guess the advice, but theoretically the options are: to offer it to all adolescents aged 12-15; offer it only to those considered high risk, or not bother with it at all.
The argument for vaccinating the whole of this age group is that there is both personal benefit to the child in avoiding Covid-19 and public benefit in more protection for the wider community. Considering that 1.25 million of our population are under 18, leaving such a large tranche open to developing and spreading the virus would not seem wise.
But is it really necessary to offer it to all 12-15-year-olds, if their risk of getting ill with Covid-19 is so small?
“If it’s safe and it’s effective, we’re all for it,” says Leahy of a lower-age vaccine. That’s a personal view but he thinks it would be representative of the medical community.
Although the majority of children don’t seem to be particularly susceptible to severe illness with the virus, “there are some groups who we would be a little bit anxious about still and we would like to see them vaccinated”. There would be both benefit to the individual getting the vaccine and to society too, preventing a child inadvertently infecting an older family member, for instance, he says.
There is a small number of children for whom the virus has been very problematic due to a delayed immune response, typically around four weeks after the initial infection. This exaggerated inflammatory response, which makes a child quite unwell, has a variety of names but here in Europe, it’s known as PIMS TS, short for paediatric inflammatory multi-system syndrome, temporarily associated with SARS-CoV-2.
“We are seeing a trickle of cases,” reports Leahy, who estimates there has been in the region of 50 to 60 cases since the pandemic started, “but that may be an under-estimate or over-estimate”.
There is no definitive blood test so identification depends on clinical diagnosis. Most of these children end up in Crumlin, even if initially seen elsewhere, because part of the assessment is a cardiology review that would be carried out there.
There was a spike of PIMS TS cases last summer after the first wave of the pandemic, and then more in January and February after the latest surge. The majority of these were aged six to 10 years and most of the children affected were previously in full health. “We’re still seeing one or two pop up but the numbers are beginning to tail off as the community transmission has decreased.”
The main focus, up to now, has been trying to protect everybody from hospitalisation and death but, says Prof Susan Smith, a Dublin GP and professor of primary care medicine at RCSI Medical School, there is increasing literature on long Covid, with children and adolescents among those affected.
What are we hearing about children and long Covid?
Taking the definition of long Covid as three months on from the initial infection, says Smith, a member of the Covid-19 expert advisory group of the Health Information and Quality Authority, UK figures show that 7 per cent of the 2-11 age group still have symptoms at 12 weeks. For the 12-16 age group, 8 per cent seem to be affected by long Covid and among those aged 17-24 it is 11 per cent.
This data suggests that long Covid, while not common among children and adolescents, “is not unusual” either, she comments, “and considering they are quite long and debilitating symptoms, they could have quite an impact on somebody’s education, for example”.
Leahy regards long Covid as “a bit tricky” to diagnosis. “Some of the symptoms are vague and hard to pin down and can they really be connected with an infection two or three months previously?”
However, he does expect to see cases in older children coming to the attention of hospitals. “Anecdotally we have had one or two inquiries from older children but in younger children we haven’t really seen it to be honest.”
Has this vaccine been tested on actual adolescents?
Yes, of course. Pfizer enrolled 2,260 volunteers aged 12-15 in its US-based trial, giving half the same vaccine that is used in adults and the other half a placebo. None of the adolescents who received the vaccine developed symptomatic infections, while there were 18 cases of Covid-19 among those didn’t. The vaccinated adolescents also produced strong antibody responses and experienced roughly the same minor side effects as people aged 16 to 25 (eg soreness at site of injection).
Moderna and Johnson & Johnson have also been testing their vaccines among 12- to 18-year-olds, with data from Moderna’s trial, at least, expected relatively soon.
Why did they not test them on younger age groups at the outset?
Children were not involved in the original adult trials for Covid-19 vaccines for a number of reasons. These include the fact that severe illness is more common among adults, specifically older adults, and also there was an urgent need to produce a means of counter-acting the virus in this global pandemic. Therefore an incremental approach has been taken to bringing these new vaccines to market.
Are the trials moving on to the under-12s now?
Yes. Pfizer has started a trial working through three age groups: five to 12, two to five years and six months to two years. Phase one is a dose-finding study, followed by phases two and three to evaluate safety, tolerability and immunogenicity. Approval for use of the Pfizer/BioNTech vaccine in children aged two to 11 in the US will be sought as early as September, according to the New York Times. Moderna is also testing its vaccine on six months to 11 years.
Oxford University says on its website that the trial of the AstraZeneca vaccine in children “continues with no safety concerns”. However, in the light of the recent recommendation in the UK that people aged under 30 be offered an alternative Covid-19 vaccine, as a result of its association with very rare blood clotting disorders in younger people, no more children are being recruited for the trial.
Would offering a vaccine to under-12s be desirable here?
There is a discussion to be had about vaccinating under-12s, says Leahy, but research shows that vaccinating children against flu does help to protect the older population.
“If you have a safe and effective vaccine, why not give it?” is his personal view. “The vaccine will always be safer than the virus; with the vaccine you control the amount and you control the time. With the virus, you don’t know what viral load the patient will get and you don’t know when they’ll get the virus.”
Aren’t parents going to be hesitant about allowing teenagers and younger children to be vaccinated?
With the under-18s, there is likely to be a lot more caution from parents, acknowledges Smith. While the age of medical consent is 16, doctors assess a teenager’s decision-making capacity and, if a parent is not giving consent, why that is.
It would be an interesting ethical consideration on whether a vaccine could be given to a teenager aged 16 or 17 against a parent’s wishes, she muses. But if the situation was reversed in the 12-15 age group, most doctors would not override the child’s view, even if the parents wanted them vaccinated.
At the outset there was concern there would be considerably more “vaccine hesitancy” among adults here than has been the case. However, Smith believes that the effects of the pandemic have been such that “everybody is prepared to take some risk to end what we’re going through”.
While vaccine trials are very good for showing effectiveness, they are never big enough to show very rare side effects, she says. However, in this case, she points out, millions and millions of young healthcare workers worldwide have been vaccinated by now without concerning side effects and there is “no reason teenagers would be different to people in their 20s”.
She also wants to make it clear to parents who might have reservations about vaccinating a still developing child or teenager, that an mRNA vaccine, such as the Pfizer and Moderna, doesn’t go into the nucleus of a cell, so it “doesn’t go anywhere near your own genetic material at all”.
The uptake of the flu vaccine that was offered free to the 2-17 age group here for the first time last winter might be a good indicator of parents’ attitudes?
They’re not directly comparable but certainly the uptake of that vaccine was less than expected, even though parents were warned by the HSE that “children are more likely than adults to get severe complications of flu”. This vaccine, offered from October until the middle of February, was administered through a nasal spray, so fear of needles was not a consideration.
Complete data for the 2020/2021 influenza season will not be available until the end of year, says an HSE spokeswoman, but to date there have been 225,614 payment claims from GPs and pharmacists for the administration of the vaccine to children aged two to 17. Some 600,000 doses for this age group were purchased by the HSE, of which 480,000 were distributed but 120,000 had to be destroyed after their expiry date.
The UK introduced a flu vaccination programme for children back in 2013, and records show uptake has increased year on year ever since.
From September onwards, it looks like schools will be most widespread gathering points for the unvaccinated, so what steps can be taken there?
Already schools appear to be very safe, says Smith, and transmission of the virus that has occurred in those communities is probably more likely due to after-school interaction among pupils. As there are already plans to vaccinate down to age 16, that will, in time, cover fifth- and sixth-year students.
She believes it would also be worth considering offering vaccination to all aged 12 to 15, but at least to the vulnerable children in that age group. While there seems to be an enthusiastic lobby for antigen testing and applying that to schools, she is not so sure.
Research shows that the benefits of testing asymptomatic people in low prevalence community settings is questionable. An expert group convened by the Government was split on the role of rapid antigen testing in suppressing Covid-19 and reopening society.
Its final, "majority report", which recommended widespread use of the tests, including the potential for mass rollout in schools by September, was not supported by two senior doctors in the six-member group that was chaired by the Government's chief scientific adviser Mark Ferguson.
Unlike PCR testing, which looks for the RNA of the virus, antigen tests look for specific proteins made by Covid-19. The tests, which take 15-30 minutes to produce a result, are much cheaper but generally less accurate.
Smith’s fear is that “false positives” would leave children having to isolate needlessly and disrupt their education.
Even if it is decided to roll out vaccinations right down to infancy, that won’t happen overnight so what symptoms do parents need to continue to watch for?
Leahy wants parents to be aware of PIMS TS and on the lookout for fever without an obvious explanation such as a runny nose or ear infection. Other symptoms would include rash and red eyes. If concerned, go to a GP or local A&E.
Most of the children they have seen with PIMS TS either had Covid themselves or had been exposed to somebody who had it. However, that child may or may not have been symptomatic and may or may not have been tested.
Generally, while the virus is still around, if a child has fever, cough and shortness of breath, he or she still needs to be assessed for the virus, he stresses.
Parents need to take the usual precautions of keeping an eye on sick child, says Smith, with the Covid symptoms of coughs, temperatures, rash and headaches being very like other viral infections. But they must also continue to be vigilant about any risk of their child spreading the virus, and not send them to creche or school but get them tested.
The positivity rate in testing of under-18s is about 2.4 per cent, she reports. As most of these are being tested because they are symptomatic, although some are close contacts, the indications are there is not a high prevalence of the virus among this age group.