Research, published in the Archives of Disease in Childhood, looked at COVID-19 cases in children in the first wave of the outbreak in England.
Prof Adilia Warris, Paediatric Infectious Diseases Specialist, University of Exeter, said:
“Dr Ladhani and colleagues present real-live data with respect to the epidemiology of SARS-CoV2 infection in infants and children in England and a comparison is made with the epidemiological figures in the adult population.
“The data is strong (systematically collected) and reinforces that SARS-CoV2 infection affects only a very small number of infants and children, and leads rarely to severe Covid-19 disease with no excessive mortality figures. Figures as shown by Ladhani and colleagues (e.g. 1.1% of all positive Covid-19 cases were children; only 4% of children presenting with an acute respiratory tract infection tested positive for Covid-19) are in the same range as earlier reported. The strength of the current study is the high number of children tested and the direct comparison with adult data obtained simultaneously, as well as the collected the data from primary care centres to provide insight what the role of SARS-CoV2 is in causing acute respiratory tract infections in children (very small, only 4%).
“This study is not focused on the role of children in the transmission of the virus, and therefore no new insights are obtained with respect on the role of children in the transmission, although indirect (based on the low prevalence numbers in children) the data support that transmission to children is very low.
“An interesting observation is the relatively higher number of infants < 1 yrs of age affected, and more specifically the higher number of infants < 3 months of age with confirmed Covid-19. This is not surprising, as younger infants often present earlier with fever and respiratory symptoms due to a viral respiratory tract infection to either the GP and A&E services.
“The results of this study do underscore that going back to school carries a very low risk for children – while an increase in SARS-CoV2 infections might be seen, the current data provides strong arguments that those infections will in the vast majority of cases not lead to severe disease in pre-school and school-aged children.
“It would be of value to obtain more insight in the clinical course of Covid-19 disease in the younger infants, e.g. are they more severely ill when infected compared to the older infants and children.”
Prof Russell Viner, President of the Royal College of Paediatrics and Child Health, said:
“These data are high quality and very useful and confirm international evidence that children and young people as a group are little affected by this virus, even showing a slight reduction in total excess deaths. Any death of a child is one too many, however even the extremely low COVID-related death rate is an over-estimate as COVID-19 infection appeared incidental in half those who died.
“Testing of symptomatic cases can be misleading about the chances of transmission, as children are much less likely to be symptomatic than adults, however these data provide another part of the jigsaw that together tells us that children play only a minor role in this pandemic.”
Dr Sanjay Patel, Consultant in Paediatric Infectious Diseases and Immunology, Southampton Children’s Hospital, said:
Is this robust science; what are the strengths and limitations of the study?
“This is a well conducted study using routine reporting data aggregated at national level (PHE enhanced national surveillance data). It is important to recognise that the denominator for this dataset is children with symptoms consistent with COVID-19, with an epidemiological link to COVID in a symptomatic child initially being required to justify testing, and admission to hospital with symptoms consistent with COVID being required to justify testing later on in the study period. This testing strategy means that this study is unable to inform us about the proportion of children infected with COVID at population level, because a significant proportion of infected children potentially displayed no symptoms (asymptomatic infection). However, it is extremely encouraging that the results of this study mirror the international data on COVID-19 in children, in terms of the rate of infection in symptomatic children being extremely low compared to symptomatic adults, and the mortality from COVID being extremely low in children compared to adults. Only 4% of symptomatic children who were tested were COVID positive, compared to 19.1-34.9% of adults. Of the 8 children who died whilst being infected with COVID-19, only 4 were thought to have died directly due to COVID-19. All of these deaths occurred in older children (aged 10-15 years). And modelling suggests no increase in excess deaths in children during the 1st wave of COVID-19 based on predictions using historical trends.
Is this study about infection, disease severity, or transmission (or all three)?
“This study is addressing the issue of rates of infection and severity of disease in symptomatic children. It is not trying to provide insights into rates of transmission or rates of asymptomatically infected children.
Does the press release accurately reflect the study?
“The press release accurately reflects the study and the additional comments by the lead author are extremely insightful.
Is it the case that children don’t seem to be an important source of infection; do we know why?
“Children do not appear to be an important source of infection and this study support this view.
Does this study have implications for children going back to school?
“This study has significant implications for schools. It suggests that children have low rates of COVID-19 (although it must be recognised that most of the sampling was conducted during the period of lock-down). It also suggests that rates of infection are lower in primary school aged children than secondary school aged children (which has also been demonstrated in studies from other countries). This has implications in terms of infection control strategies in primary schools and secondary schools (in terms of robust enforcement of social distancing and potentially additional measures in secondary school settings). However, one also needs to acknowledge that although these data are encouraging and suggest that children are not super-spreaders of COVID-19, the study was not set-up to investigate the rate of transmission between children. For this reason, we need to ensure that robust infection control measures remain in place in schools (especially secondary schools) and that vigilance is maintained (through test and tracing) once schools reopen.
Does this study say anything about any differences in different ages of children?
“This study suggests that rates of infections are lower in younger children (aged 1-9 years) compared to older children (aged 10-15 years).”
Dr Mike Tildesley, Associate Professor, University of Warwick, said:
“This study adds to the growing body of evidence regarding the risk to children of the COVID-19 pandemic. It has already been widely recognised that children only account for an extremely small proportion of confirmed cases and that most children have only mild symptoms or are completely asymptomatic. This paper indicates that, despite the increase in testing that has taken place in recent months, the rate at which children test positive is still significantly lower than adults and importantly that there is no evidence of an increase in child mortality as a result of the COVID-19 epidemic in the UK. This is a robust and comprehensive study, led by a team at Public Health England. It is important to note that this study is based upon positive test results and (as the authors themselves acknowledge) it is possible for false negative results to be obtained, particularly in individuals that do not display symptoms. Given that children tend to be less symptomatic, we may expect that the proportion of infected children is slightly underestimated.
“That said, these results provide further supporting evidence that the re-opening of schools in September should represent an extremely low risk to any individual child, though it is important to recognise that, despite these low numbers, we would expect that children may play a role in the transmission process. With this in mind, the vast majority of parents should feel reassured regarding the safety of their children when schools re-open, though given the likely role of infected children in transmission, parents and teachers with underlying health conditions may need to take precautions in order to minimise their own risk over the coming months.”
Prof Jonathan Ball, Professor of Molecular Virology, University of Nottingham, said:
“This data is heavily skewed by the very fact that the only children tested were those presenting at a GP clinic with well-defined respiratory illness and fever. We know from other studies that children, particularly young children, show minimal symptoms of SARS2 infection and often have no symptoms at all. Therefore, the fact that children weren’t often amongst confirmed cases of COVID-19 isn’t so surprising. To imply that children aren’t an important source of the infection isn’t really fully supported by the evidence here – the study doesn’t look at the infectiousness of children.
“What the paper does highlight however, is how poor our testing capacity was as the first wave was about to hit the UK. The fact that we weren’t able to perform wider surveillance in mid- to late- February meant that the UK was hit with lots of separate introductions of the virus, mainly from supposedly unaffected countries and regions. By the time we realised we had a problem it was too late. This is a stark reminder of the importance of timely and efficient test, track and trace as we try to stave off a second wave.”
Prof Paul Hunter, Professor in Medicine, UEA, said:
“This paper presents an important summary of the first wave of the COVID-19 epidemic in the UK up to the 1st of May. The data used were based on reporting of sampling undertaken usually in response to a clinical need, what would now be called pillar 1 tests. Based largely on the finding that children represented only 6.6% of all people tested and that only 4% of children tested were positive compared to 34.9% of adults testing positive, the authors conclude that their findings “provide further evidence against the role of children in infection and transmission of SARS-CoV-2”. This is repeated in the press release: “The findings confirm that, unlike adults, children aren’t an important source of COVID-19 infection, say the researchers”.
“Whilst it is generally accepted that children even when infected are unlikely to become ill with COVID-19 and very unlikely to die, this is not evidence against the role of children in the transmission of SARS-CoV-2. I do not think the authors of this study can use their data to draw such an apparently firm conclusion.
“1. It does appear from previous work that a lot of the transmission during March and April was associated with hospitals and care homes. From PHE’s own data, the highest attack rates per 100,000 population were in the over 45 and especially the over 75 age groups. As such children are likely to have been protected to a large extent at that time.
“2. Since May, the 15-44 year age group seem to be where most infections are occurring and as the attack rate in the over 45s has dropped dramatically the attack rate in the under 14s have remained constant so children represent a much greater proportion of all cases in June and July than found in April and May (https://www.gov.uk/government/publications/national-covid-19-surveillance-reports).
“3. As pointed out by the authors much of this testing was for clinical reasons and there is little indication that asymptomatic children were tested and also given the high prevalence of fever in this age group from a wide range of other infections, it is not surprising that the swab positive rates were somewhat lower than in adults.
“4. Looking at the Cambridge nowcasting website (https://www.mrc-bsu.cam.ac.uk/now-casting/) the 5 to 14 year age groups appears to be the one age group that have had the highest probability of infection.
“So I for one do not think the key conclusions as stated in the paper are sound based on the data presented. I do not think it is possible to definitively determine the contribution that children can make to the spread of COVID-19 with evidence available at present. Nevertheless our children cannot lose out on their education any more. We need a more rigorous discussion on how to allow schools to reopen safely and also on what other restrictions we may need to impose in order to keep infection rates down.”
Prof Sheila Bird, Formerly Programme Leader, MRC Biostatistics Unit, University of Cambridge, said:
“It is reassuring, but not news, that few children have died in UK – or in comparably-sized European nations – directly from COVID-19 disease or as a confirmed COVID-infection during the first wave of SARS-CoV-2 infections.
“Data from England in this report do not address transmission by children. The report reviews international data on transmission by children but does not contribute additional data from England.
“For England, the study tells us that virus-tested children up to 15 years of age numbered 35,200 (6.6%) out of 536,300 people of known-age who were swab-tested between 1 January and 3 May 2020. Since the population of England is around 55 million with about one-sixth under 16 years of age, those counts suggest that 4 per 1000 children under 16 years of age were swab-tested; compared to 11 per 1000 people aged 16+ years. Reasons for testing by age-group were not detailed, nor analysed in this study, but they do matter: whether tested by reason of symptoms, for surveillance or due to being caught up in an outbreak investigation (including in hospitals).
“For example, I’d like to know, in particular, what explains three very significantly different swab-positive rates at 1 year of age and younger, which the study does not draw attention to. Confidence intervals do not overlap and so explanation is surely warranted.
“Swab testing in children under 3 months: 272 positive out of 4,072 tested (6.7% positive, 95% CI: 5.9% to 7.4%). No indication here as to whether testing was preferentially around peak of maternal COVID-19 illness.
Swab testing in children age 3 months to 12 months: 128 positive out of 3,358 tested (3.8% positive, 95% CI: 3.1% to 4.5%).
Swab testing for 1-year olds: 107 positives out of 4,280 tested (2.5% positive, 95% CI: 2.0% to 3.0%).
“For older children (aged 2-15 years), the swab-positive rate was 901 positive out of 23,490 tested (3.8% positive, 95% CI: 3.6% to 4.1%), which is significantly higher than for 1-year olds and significantly lower than for infants under 3 months. The test-rate would also appear to be massively lower for children aged 2+ years but younger than 16 years since 23,490 tested represents fewer, on average, than 1700 children tested per single-year-of-age. Changes in test-rates and test-capacity over time are an added complication because they may affect different age-groups of children differently.
“Subsuming major differences in test-rates and in percent-positive by age-group (under 3 months, 3-12 months, 1 year, aged 2-15 years) does not negate them; nor help us to understand them.”
‘COVID-19 in children: analysis of the first pandemic peak in England’ by Shamez N. Ladhani et al. was published in the Archives of Disease in Childhood at 23:30 UK time on Wednesday 12 August 2020.
All our previous output on this subject can be seen at this weblink:
Prof Jonathan Ball: “I am working on a study looking at the early phases of the outbreak in the UK and the prevalence of community-cases of SARS2.”
None others received.