As children congregate in schools, they can spread the disease, Green adds. If infected, they are likely to be asymptomatic or experience only mild symptoms, but that does not mean all children brush off the disease easily. In the United States, hospitalisations of children and adolescents rose nearly five-fold during late June to mid-August 2021, as Delta was becoming dominant, according to data from the US Centers for Disease Control. In Israel, of all patients in a serious condition in October, between 0.2 and 0.5% were children aged zero to 19. A total of 12 children aged zero to 19 in Israel have died of Covid-19 since the start of the pandemic, according to the Ministry of Health’s Covid-19 dashboard.
Children are also at some risk of prolonged symptoms after infection, mostly headaches and fatigue, known as “Long Covid”. Although reports vary, a recent study of 258,790 children aged five to 17 found that, in the UK, between 2% and 4% of 1,734 children who tested positive for Covid-19 experienced such longer-term symptoms. In Israel, a similar study found that 11% of 13,864 children aged three to 18 who had recovered from Covid-19 reported long-term symptoms including disturbed sleep and problems concentrating; some of these effects, the study’s authors say, could result from prolonged lockdowns and school closures.
Given these factors, “it makes a lot of sense,” Green says, to vaccinate children aged 5 to 11, and possibly at even younger ages, even without underlying conditions. From Israel’s experience of vaccinating children aged 12 to 15, “the lesson is that the vaccine has a good safety record. There are not a significant number of severe adverse effects”, he adds.
Between one in 3,000 and one in 6,000 males aged 16 to 24 who received the Pfizer-BioNTech vaccine in Israel developed a rare heart muscle inflammation called myocarditis, but Green insists that it is “almost always” a treatable condition, although it may require hospitalisation. That side effect may also have to be seen in the context of the dangers of a Covid-19 infection. An Israeli study of adults aged 16 years and older found that the risk of myocarditis was “substantially increased” after infection with Covid-19, compared with its incidence after vaccination.
Other Israeli public health officials express more caution.
“Vaccinating children under the age of 12 years raises difficult medical, ethical and social issues and questions,” Adi Niv-Yagoda, an expert in health policy at Tel Aviv University and a member of the Israeli Health Ministry’s Covid-19 advisory panel, wrote in an email. “On the one hand,” he says, “vaccinating children between the ages of five and 12 years can be very helpful in dealing with the spread of Covid-19 morbidity and reducing the dimensions of the corona epidemic. On the other hand, the natural concern [is] about possible future health consequences.”
Those concerns are echoed by Nicole Ritz of University Children’s Hospital Basel. “Do you vaccinate the younger kids to protect themselves or do you vaccinate them to protect society?” asks Ritz, a pediatric infectious disease specialist who has treated between 20 and 30 children and adolescents with PIMS (paediatric inflammatory multisystem syndrome), a rare and severe syndrome which occurs in less than 0.5% of children who have (or who have had) Covid-19.
If the disease remains benign in most children, then only a small group of them prone to severe illness – those with risk factors like obesity, diabetes or lung diseases – will potentially benefit directly from vaccination, Ritz explains. But if the only benefit of immunising kids is to protect their grandparents, then “that vaccine has to be extremely safe”, she says.