Primary-age children infected with the coronavirus have much lower viral loads than adults with Covid-19, a study concluded.
Viral load – the amount of virus that a person harbors – is considered by some scientists to be related to increased transmissibility, although there is debate about these claims.
Data from public health authorities in the Netherlands reveal a 16-fold difference in the amount of viruses between people over 80 and children under 12.
Rapid antigen tests, such as the touted 15-minute screening used in schools and airports, are also likely to be less accurate for children than for adults because of the lower load, the researchers say.
Scroll down to see the video
79 years old) and the youngest (” class=”blkBorder img-share” style=”max-width:100%” />
This graph shows the Cp value for patients with coronaviruses classified by age. Cp is a measure of how many cycles of PCR analysis, which amplified a genetic signal, are needed to detect a SARS-CoV-2 signal. The higher the number, the lower the viral load. ‘Median Cp values between the older (> 79 years old) and younger (<12 years old) population differed by more than 4 cycles of CRP, suggesting an approximately 16-fold difference in viral load,' the researchers wrote.
Children are more at risk of contracting the new variant of the coronavirus than the previous strain, government advisers revealed today
More than a quarter of a million people in northern Holland were tested between January 1, 2020 and December 1, 2020.
Of these, 211,933 were performed by qualified health professionals, with viral load data available for 18,290.
All of these swabs were processed by the same regional laboratory in the Netherlands to ensure that the tests were processed and analyzed in the same way.
“As far as we know, this is the first study to assess SARS-CoV-2 viral load distributions in a large number of patients from different patient categories,” wrote the researchers in their study, which has not yet been peer-reviewed. and is published online as a prepress.
“Our data show a clear relationship between age and SARS-CoV-2 viral load, with children (under 12) having lower viral loads, regardless of sex and duration of symptoms.”
More than 2,500 of the people tested were under 20 and 238 of them were under 12, equivalent to the age of primary school.
A metric used to quantify viral load is Cp, which indicates how many cycles of PCR – which replicates and amplifies genetic material – are needed before the virus is detected.
The higher the value, the lower the viral load, as it indicates how many cycles of amplification were needed.
In the study, the researchers note that the difference between the average Cp value for those over 80 and under 12 years old is more than four cycles, equivalent to a 16-fold increase.
Coronavirus infection can cause forms of paralysis in some rare cases in children, reveals a new study (stock)
“The most striking finding in this study was the relationship between SARS-CoV-2 viral load and age, with significantly lower viral loads in children,” add the authors of the Kennemerland study in northern Holland.
“As previous studies have suggested that young children play a limited role in the transmission of SARS-CoV-2, our data support this suggestion.”
Throughout the pandemic, there was a mystery as to why children are not relatively affected by Covid-19, when adults are severely affected.
During the coronavirus pandemic, children were far fewer cases than other respiratory illnesses, including influenza.
The main theory for this is due to the way the coronavirus enters human cells, through a receptor called ACE2, found in many cells of the upper respiratory tract.
As a result, Professor Wendy Barclay of Imperial College London, a member of NERVTAG, explained last month that this made adults ‘easy targets’ compared to children.
This is because the amount of ACE2 that a person expresses naturally and steadily increases over time, with young children having very little and people.
ACE2 is the receptor on the surface of human cells that the coronavirus hijacks and uses to infect.
Dutch researchers point out that antigen tests, which are faster, but not as reliable as CRP tests, are even less accurate when used by an infected patient with a low viral load.
In infected children under 12, the viral load recorded was less than 30 in almost a third (31.1 percent) of cases, almost twice the proportion of people with this low reading in all other age groups.
As a result, the researchers say that ‘the SARS-CoV-2 antigen tests may be less sensitive in children than in adults’.