It was children, teenagers and university students who set off the second wave of coronavirus when summer ended so, although they are much less likely to die of severe Covid-19 than adults, infections among them must still be taken extremely seriously.
Globally, scientists have been studying the immunity response among people infected with covid-19.
Of the eleven studies that attempted to isolate the live virus, all eight studies included that used respiratory samples successfully managed to culture viable virus within the first week of illness.
"By studying these multiple compartments of adaptive immunity in an integrated manner, we observed that each component of SARS-CoV-2 immune memory exhibited distinct kinetics", the researchers wrote in the study.
There have been concerns that the immunity produced after treatment of coronavirus could be short-lived and that the recovered patient may get sick again.
"The majority of subjects had a mild case of COVID-19, not requiring hospitalization; 92% of subjects were never hospitalized for COVID-19; 7% of subjects were hospitalized, some of whom required intensive care unit (ICU) care", the authors of the study said.
Dr Rose Penfold, an epidemiologist at King's, said: "Older, frailer people are at greater risk from COVID-19 than those who are fitter, and our results show that delirium is a key symptom in this group".
Attorney General Fox Participates in Lawsuit against Apple
Rather than disclosing these issues or replacing batteries, however, Apple concealed the issues from consumers. The company in 2018 tweaked its settings to make its battery-management practices clearer to users.
The research, published online, has not been peer-reviewed nor published in a scientific journal.
During the study, 89 of 11,052 staff without antibodies developed a new infection with symptoms while none of the 1246 staff with antibodies developed a symptomatic infection.
Since the beginning of the Covid-19 pandemic in December 2019, the highly infectious SARS-CoV-2 has infected more than 56.5 million people and claimed more than 1.35 million lives worldwide. Only three (0.24 per cent) of these people later tested positive, and none of them went on to develop symptoms.
"Prior SARS-CoV-2 infection that generated antibody responses offered protection from reinfection for most people in the six months following infection", the Oxford study said.
The viral genome sequencing data will be integrated within the four UK Public Health Agencies and NHS Test and Trace to help understand outbreaks and strengthen infection control measures.
The study analysed the immune memory against the virus in 185 patients who had recovered from COVID-19.
"The duration of immunity is unclear, but it does make sense that we may start seeing cases of reinfection with the novel coronavirus, as with other common coronavirus infections", he said.
The Oxford clinicians say it is too soon to say whether or not there is long-term protection beyond six months, but call the findings "encouraging and exciting".