Early in South Africa’s fourth Covid-19 wave, dominated by the Omicron variant, concerns were raised on what appeared to be an increase in hospitalisations among children. At that point, it was unclear whether children were being hospitalised due to more severe disease than with previous variants or whether something more complex was occurring. 

Increased hospitalisations but less severe disease 

According to Dr Waasila Jassat, Public Health Medicine Specialist at the National Institute of Communicable Disease (NICD) and Lead on the NICD’s Datcov Covid-19 hospital surveillance programme says, South Africa and other countries during the Omicron wave reported higher rates of hospitalisation among children, particularly children under five years of age.

“Our analysis has shown that just like adults, children have lower requirement for oxygen, treatment in ICU, severity and death in the Omicron wave compared to previous waves. Even in other countries, while more children have been admitted, they had had less severe disease,” she says. 

People experienced different symptoms with the Omicron variant than with Delta, according to Jassat, and many children presented with non-respiratory symptoms like nausea and vomiting.

“Our surveillance data shows 30-40% of patients admitted in the Omicron wave had incidental positive tests, i.e. they were admitted for other medical reasons or surgery and tested positive for SARS-CoV-2,” she adds.

What the Western Cape data shows about Omicron in children

Prof Mary-Ann Davies, a public health medicine specialist working for the Western Cape Department of Health and Director of the Centre for Infectious Disease and Epidemiology research at the University of Cape Town says that while it was observed that children diagnosed with Covid-19 were at a greater risk of hospital admission compared to previous waves, exactly what this means is difficult to interpret due to all the changes in protocols since the first and second wave.

“In the 3rd and the 4th wave we did a lot more testing of people that were coming into hospital and in children specifically,” says Davies.  

She says that a lot of children in the Western Cape presented to hospital during the fourth wave with respiratory illness, some with Covid-19, while others had Covid-19 plus another viral infection.

This makes it difficult to know whether more hospital admissions with Covid-19 were seen in the fourth wave simply because there were more hospital admissions among children in general and incidentally, they tested positive when admitted or if Covid-19 infections were driving the hospitalisations. 

She adds that the paediatric hospitals in the province reported being busy and there were many children in hospital with Covid-19. Yet, when compared to hospitalisations in children in previous waves, many were sick enough to need hospitalisation, but generally, they weren’t severely ill.

A potential reason for the higher rates of Omicron presentation in children, according to Davies, is the variant’s predilection for infecting the upper respiratory tract. 

Vaccines offer less protection against Omicron, but still reduce risk

According to Davies, there is currently not any child-specific data in South Africa about how much protection vaccination has provided against infection with the Omicron variant. “We don’t know about protection against infection for children in the Omicron period and really in our setting so few children were fully vaccinated before the 4th wave that we can’t really assess from our data,” she says. 

“But certainly, protection against severe disease does seem to be maintained in people, even if they do get infected. I think we’ll have to watch that space. There’s no reason to think that the vaccine would be less effective in children,” she adds.

So far, studies in adults have generally found that the leading Covid-19 vaccines are still effective against Omicron, although efficacy is lower.

Some local evidence comes from private Medical Scheme Discovery Health, which conducted a study published in December 2021 in collaboration with the South African Medical Research Council. They looked at vaccine effectiveness based on data from the first three weeks of the fourth wave. Discovery noted that the findings are preliminary and may change as the wave progress and that the data is confounded by various factors such as high sero-prevalence of Covid-19 antibodies in the South African population.

“What Discovery found was that two doses of the Pfizer vaccine basically gave you about a 33% protection against infection, which is much worse than with the Delta variant where it was around 80%,” says Professor Haroon Saloojee, a Professor of Child Health at the University of the Witwatersrand. “But the better news was that two doses offered about the 70% chance of preventing a hospital admission, which again wasn’t as good as the protection previously of 93% against other variants.” 

Davies says that although the protection against Covid-19 infection offered by the current vaccines against the Omicron variant is lower than what they would like, there is still a reduced risk of infection, which will make a difference. “The fact that the current vaccines are not going to eliminate Covid-19 doesn’t mean they’re useless at the level of the population. If everybody’s risk is reduced even by 10 or 20%, that makes a big difference,” she says. 

Should kids get vaccinated?

The only Covid-19 vaccine currently approved for children aged 12 to 17 by the South African Health Products Regulatory Authority (Sahpra) is that of Pfizer/BioNTech. Initially, only one dose for this age group was provided. A National Department of Health circular notes that children 12 to 17 are now eligible to receive two doses given 42 days apart.

By 13 February, a total of 1,375,425 vaccinations had been administered to the 12 to 17-year-old age group, according to the National Department of Health’s vaccination dashboard. 

Sahpra has not yet given the green light to use any Covid-19 vaccine in children younger than 12. In addition to children aged 12 to 17, the United States Food and Drug Administration has also approved the Pfizer/BioNTech Covid-19 vaccine for children aged five to 11 — they have not yet taken a decision on kids younger than five.

Saloojee points out various benefits to eligible children getting their jabs. “The three main advantages are that it lowers the risk of an individual child getting very sick. It increases the chance of doing their activities of daily living and it also reduces the chance of transmission to other people in society,” he says.

Davies agrees that vaccinating children has several benefits, although she argues that older persons and those with comorbidities should remain the main priority when allocating vaccines and resources. 

“[There are the] benefits at the individual level of no severe disease and the second benefit of not getting Covid-19.  Even though the infection protection is not 100%, you do have a lower risk. Then the third benefit is really for the people around the children,” she says. 

One factor that may be influencing vaccine uptake among children, Davies suggests, is the perception that Covid-19 is really mild in children and that it might even be good if they got infected because it will offer better immunity. She says that the risk of severe disease in children is not zero, and some children have gotten really sick.   

“Yes, an infection might give you great protection against future disease, but getting infected means that you have to be at risk of severe disease. And why would you do that?”  

She adds that someone who gets vaccinated and then gets Covid-19 will have protection against severe disease as well as the extra immunity acquired post-infection.

What new regulations mean for children

South Africa’s Adjusted Alert Level 1 regulations were recently amended, reducing the isolation period from ten to seven days. It also states that anyone who tests positive for Covid-19 but doesn’t have any symptoms does not need to isolate anymore.

School children have also returned to attending classes full time, following an announcement by the Minister of Basic Education. 

Spotlight asked Jassat and Davies what implications this could have for Covid-19 infections among children. 

According to Jassat, “There are some risks of transmission and outbreaks in schools, but these can be mitigated through mask-wearing, observing distancing where possible, and having well-ventilated classrooms. There is a bigger cost to children in closing schools.” 

Davies says that generally very few of the cases of Covid-19 overall and especially in children are diagnosed. And if they are, it’s usually diagnosed after the most infectious period. This is further complicated by many children having Covid-19 but being asymptomatic. And so, the changes in regulation to not require isolation of asymptomatic cases or to no longer require close contacts to quarantine will likely not have a huge impact on infections. 

She says that what may lead to some increase in Covid-19 transmissions and infections is the psychological effect of the changes. “The regulation changes make us all think it’s safer to socialise more… and being in contact with one another more, especially if we relax our distancing and mask-wearing could result in some increases in transmission,” she says. DM/MC

*This article was published by Spotlight – health journalism in the public interest.