Kids’ vaccine awaits approval
VACCINE maker Moderna requested emergency use authorisation yesterday of its Covid-19 vaccine for babies, toddlers and young children – a highly anticipated step towards making shots available to the last group in US society lacking access.
The path to a vaccine for the youngest children has been tortuous, marked by disappointing results, delays and confusing communication – and in the meantime, as many as 75% of children have been infected with the virus since the dawn of the pandemic, according to a new study.
Moderna’s announcement will intensify pressure on the Food and Drug Administration (FDA) to move quickly, as parents, paediatricians and politicians have become increasingly impatient about the lack of vaccines and treatments to protect young children.
Politico reported last week that the agency may not make a decision on the vaccine until June and was leaning towards reviewing the Moderna shot for children younger than 6 alongside a three-dose regimen from Pfizer and German partner BioNTech. That has stoked anger and suspicion among some parents, who maintain that the agency is delaying vaccines.
The findings on the Moderna paediatric vaccine are not the slam dunk the public has grown accustomed to when results have been released on coronavirus vaccine studies. That largely reflects the emergence of the Omicron variant.
Trials of vaccines for young children have been designed to show whether, in laboratory tests, the shots generate an army of disease-fighting antibodies equivalent to or better than the response that protected young adults earlier in the pandemic.
Moderna’s study showed that its two-shot vaccine regimen – each shot is a quarter of the dose given to adults – was successful in mustering an immune response in children younger than six similar to what had been found in the blood of young adults.
But there’s a difference between showing success in a lab test and protecting people in the outside world, especially as the Omicron variant rampaged. Amid the Omicron surge, two shots were only modestly effective in preventing illness caused by that variant, mirroring the performance of the vaccine in adults.
Moderna’s updated analysis showed it was 51% effective in preventing illness in children between six months and 2 years old and 37% effective in children 2 to 5 years old.
Doctors expect that protection against severe illness would be stronger, but because hospitalisation and death are rare outcomes in children, there were no cases in the trial, and no conclusion could be drawn about the protection the vaccine provides against severe illness. Moderna said the vaccine proved safe and well-tolerated in its trial, which included 6 700 children under the age of 6. Fevers occurred in about 15% of 2-to-5-year-olds in the trial and 17% of the children between 6 months and 2 years old.
Next, the FDA will scrutinise that data. The presence of the Omicron variant is likely to frame the debate about the vaccine, making it harder for experts to agree about what constitutes a successful shot, particularly in young children who rarely suffer severe illness after infection. The benchmark for success has in many ways become outdated because the level of antibodies that protected against the original Covid-19 strain no longer offers substantial protection. Many experts agree that the Omicron variant has made it clear a booster dose will be needed, including in young children. The third dose improves and broadens the immune response against variants. But some argue that a two-shot course should be authorised, even if a threeshot regimen from Pfizer-BioNTech may be authorised close behind.
“The sooner, the better in my mind. It doesn’t matter if it’s Moderna or Pfizer or both,” said Sunanda Gaur, a professor of paediatrics at Rutgers Robert Wood Johnson Medical School.
The finding that most children have already been infected may also become part of the discussion. Many physicians favour the additional protection afforded by vaccination because it is not known how long immunity from an infection lasts, and it is clear that reinfection can occur. Still, most children are at low risk of severe illness, raising questions among some parents, and even specialists, about how vaccines should be used.
“Does a universal campaign to vaccinate all kids, does it still make sense?” asked Richard Malley, an infectious disease doctor at Boston Children’s Hospital, while emphasising the importance of vaccinating children at risk of complications from infection.
Peter Marks, the director of the FDA’s Centre for Biologics Evaluation and Research, said at a senate committee hearing that the agency will “move quickly without sacrificing standards to finish our evaluation of Covid-19 vaccines for children under 5”.
But, he said, “we can’t actually finish our reviews until we have complete applications”. A senior Biden administration official said Moderna was expected to file all of its raw data by early in the second week of May.
It is unclear whether the FDA will review Moderna’s entire data submission at once, which includes findings on children up to the age of 17, many of whom already have access to the Pfizer-BioNTech vaccine. Moderna’s paediatric vaccine programme has been stalled for almost a year because of concerns about rare cases of heart inflammation in adolescents. Some parents have called for the agency to prioritise young children because they don’t have access to any protection.
But the FDA has had a head start on reviewing some of the data on older age groups. Last year, Moderna submitted its authorisation for adolescents between the ages of 12 and 18 and sought authorisation of a shot for children 6 to 11 a few weeks ago.
The picture could grow more complicated in coming weeks because results for the Pfizer-BioNTech paediatric vaccine may be reported even as the FDA scrutinises Moderna’s data. |