‘More questions than answers’: COVID vaccines still not authorized in Canada for children under 5

'More questions than answers': COVID vaccines still not authorized in Canada for children under 5

Even as Canadians struggle with a sixth wave of COVID-19 infections, children under five are the only age group in Canada without access to vaccines designed to protect against the virus.

As of April 27, Health Canada has not received applications from any vaccine manufacturer requesting authorization of a COVID-19 vaccine for children under the age of five. However, Moderna says it is currently working on submitting it to Health Canada for approval.

The lack of vaccines, coupled with high levels of community transmission, may make some parents concerned about their youngest children being exposed to the infection.

Dr. Martha Fulford is an infectious disease specialist and chief of medicine at McMaster University Medical Center in Hamilton, Ont. She said that until a vaccine is proven to provide significant protective benefits to the youngest children, there is no reason to rush the process.

Fulford told CTVNews.ca in a phone interview, “You can’t vaccinate a zero to four-year-old until you have a vaccine that actually does something for the child, and where the benefits are. Any potential risk is outweighed.” on 25 April. “Eventually, I think we’ll have one, but don’t rush it.”

Pfizer Inc. and BioNTech SE are currently in the process of making a vaccine for children under the age of five, while Moderna Inc. is working on developing its own version of this vaccine for children under the age of six. The preliminary data published so far is limited to press releases shared by pharmaceutical companies.

In the case of Pfizer-BioNTech, an ongoing clinical study is evaluating the efficacy of vaccines for children aged six months to four years. After two doses, the company noticed that the vaccine did not meet its criteria for immunogenicity, said Dr., a pediatric emergency physician based in Toronto. Dina Kulik said. This means the vaccine was unable to elicit an effective antibody response among the people involved in the study, she said. The company has instead decided to expand its trial to include a third dose. Pfizer expects to release this data in May, before being evaluated by the United States Food and Drug Administration.

“It was not approved because it was not effective, quite frankly,” Kulik told CTVNews.ca in a phone interview on April 21. “He didn’t do what it’s meant to do, so why would we give a vaccine… if you’re not seeing the benefits?”

While it can be disappointing to see that two doses of the vaccine were not as effective in children under five years of age as they were initially in adolescents or adults, vaccine products manufactured for children face delays and later Entering the market is normal. Compared to products made for adults, Montreal Children’s Hospital pediatric infectious disease specialist Dr. Jesse Papenberg said.

“We have all become accustomed to such rapid success in terms of randomized control trial data showing tremendous effects so quickly for adults,” he told CTVNews.ca in a phone interview on April 26. “It’s really not unusual for vaccine development. For children [to] In terms of those studies take longer and really try to find the lowest possible dose that elicits a protective immune response. ,

The data released by Moderna is based on a study involving children aged six months to five years, whose results are split between two age groups – those who are six months and one year old, and those who are two to five years old. are between the ages of. The results showed that the two doses of the vaccine had an efficacy of 43.7 and 37.5 percent, respectively, in both groups. The company recently submitted an application to the US FDA to authorize its vaccine.

Both drug companies are expected to submit their applications for approval to the FDA before submitting them to Health Canada, Papenberg said, although it is likely that Canada will respond to these requests for authorization within days or weeks of being filed in the US. can see. The goal of this review is to determine whether the products work and are safe to use, he said.

“These companies prioritize the US market because FDA approval carries some weight internationally,” he said. “I expect to receive submissions to Health Canada, if not by the end of May, then sometime in June … based on the information the FDA has provided with its anticipated deadline.”

However, given the currently available data on the efficacy of these vaccines, Fulford said he is not entirely sure they will confer a strong benefit to children under the age of five. He said more data is needed to assess how much these vaccines will reduce the burden of COVID-19 among children in this age group, and before doctors are able to make recommendations on their use. How safe they would be, she said.

“For me, there are more questions than answers at this point,” Fulford said. “You have to have a really compelling case that there’s going to be a significant benefit from doing this.”


‘High bar’ for vaccine effectiveness in children

According to Fulford, the bar for the development and approval of vaccines for children is much different than for adults. This stems from evidence that children are at lower risk of poor outcomes from COVID-19 infection, she said. Studies have shown that the risk of serious illness from virus infection increases with age.

“Kids have a much higher bar in terms of the effectiveness of vaccines … and you have to make sure you’ve discussed adverse outcomes,” she said. “When you have the lowest risk group of people [severe] The consequences of the disease, you should have the highest protection bandage.”

Papenberg echoed this sentiment, saying the goal is for manufacturers to produce vaccines with the smallest doses possible.

“The idea of ​​using the lowest possible dosage, in fact, stems from a desire to make a product as safe as possible, given that the disease we are preventing in pediatrics is less fatal than it is in adults, Papenberg said. “We hold vaccines a little too high when it comes to safety in children.”

Among the pediatric patients she is currently seeing, Kulik said common symptoms include fever, sore throat, fatigue and body aches. But especially with the Omicron BA.2 sub-version, she said she’s also noticing less respiratory distress and more vomiting and diarrhea, as well as rashes often mistaken for hand, foot, and mouth disease.

“This particular strain is causing more discomfort than what I see professionally,” she said. “It’s uncomfortable, but it’s not going to cause serious illness… Overall, the kids are doing well but they feel very awkward.”

The fifth wave is likely to cause the highest hospitalization among children under the age of five in Canada, Papenberg said. As Canadians continue to navigate the sixth wave, hospitalizations among this age group continue to be reported, but not in such large quantities, he said.

According to data collected by Public Health Ontario as of April 25, the number of children aged zero to four who were hospitalized two weeks earlier was 47 out of a total population of about 723,000. As of April 26, Quebec health officials reported just seven hospitalizations among children in the same age group. Fulford said these figures are significantly lower than hospital admission rates for some of Canada’s older populations.

As a result, it is important to set a clear target for vaccines in children, Fulford said. Based on the vaccine program launched in Canada so far, the goal has largely been to prevent the serious consequences resulting from COVID-19 infection, she said. But when dealing with an age group that is already at lower risk of these consequences, especially when compared to the older population, it means weighing the risks and benefits associated with vaccination for each individual child. important, Fulford said. This includes taking into account existing concomitant diseases, such as obesity or diabetes, which have a higher risk of developing serious consequences as a result of infection.

“Children who are at risk know who they are,” she said. “They are children who were at risk before being infected with COVID-19.”


What can be done to reduce the risk in children?

Fulford said that in addition to awaiting approval of the COVID-19 vaccine for children four years of age and younger, it remains to be seen what the guidance will be about its use.

“Accepting something is not the same as saying, ‘Everyone should get it right now,'” she said.

Once approved, Vaccination Advisory Committees are expected to place the efficacy of vaccines in a wider context, taking into account the disease burden facing the population, as well as submit recommendations on the use of these vaccines. To do relevant risk-benefit analysis.

“Is it possible that both [vaccines] Will there be a recommendation with the same strength, or will there be a preferential recommendation for one product over another?” Papenberg said. “That’s it. [the National Advisory Committee on Immunization] Equity will look within the framework of ethics, acceptability and feasibility.”

Fulford said another important question that remains to be answered is what would be the potential benefit of COVID-19 vaccination in young children who have already been infected. A study conducted in England during alpha and delta waves suggests that re-infection rates appear to be lower in children than in adults, but more recent data on the subject remains limited. In the United States, recent data from the Centers for Disease Control and Prevention shows that nearly three quarters of children nationwide have previously been infected with COVID-19.

Omicron remains the dominant version in circulation in Canada. While omicron infections appear to be mild in children, they are not insignificant, Papenberg said. Kulik said that if a large number of children become infected with the virus, it also raises the possibility that a higher proportion of these children may have serious consequences after infection.

Children attending school or daycare are particularly at risk of contracting the disease because of their high levels of interaction with others, often in settings where masks are not mandatory, she said.

“Most children and adults do well with COVID, [with] A very mild, flu-like illness,” she said. “But if you have enough people who get COVID, you’ll have enough people who get very sick with COVID, including children. It’s really It’s just a numbers game.”

While there is currently no vaccine available for children under the age of five in Canada, efforts could be made to limit the chances of these children contracting COVID-19, Papenberg said. This includes limiting social contact with others and wearing masks indoors, if possible, for people aged two and older, especially when physical distancing is not an option. Fulford said reducing risk includes avoiding crowded places, close contact and poor air circulation.

“Everything we’ve told people they can do to help reduce the risk [of contracting COVID-19]These things still apply today,” Papenberg said.

Fulford encourages parents with young children to assess the potential risks and benefits of proceeding with any activity when it comes to developing a COVID-19 infection. There may be situations where risks exist, such as when a child attends school or participates in extra-curricular activities with other children, but any associated benefits may outweigh those risks, she said.

“The risk-benefit is COVID versus no COVID – it minimizes the total harm in every aspect that affects a child’s life,” Fulford said. “It’s a balancing act for every family.”

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