Official News Magazine of the Canadian Snowbird Association



What we know − and don’t know − about immunity, transmission and getting back to (semi) normal

For many of us, seeing children with their small faces almost eclipsed by a Spider-Man or tie-dyed mask has become a familiar, if not poignant sight during the pandemic. And it raises so many questions. When will children be safe? What about play dates? Can children hug their grandparents? Can young kids spread COVID-19? Do they really need a vaccine?

The short answer is that we’re a year-and-a-half into the pandemic, and there is still much that we don’t know.

The situation isn’t helped by the more worrisome variants rolling in, with scientists still not clear on transmission rates or the long-term effects of COVID-19.  However, there is a growing field of evidence which suggests that kids may be immune to some of the most virulent effects of the virus.

How the virus affects children

COVID-19 is caused by the coronavirus when it enters the body through the nose, mouth or eyes and attaches to our cells.  From there, the virus replicates and spreads to other parts of the body and is transmitted to other people via saliva, sweat and airborne respiratory fluids.

Although young children account for only a small percentage of COVID-19 infections, they can still become infected with the virus. Many of them have no symptoms, while those who do get sick experience milder symptoms such as low-grade fever, fatigue and cough.

Why young children seem to fare better against COVID-19 than do adults is something that science is still trying to understand. One explanation may be that there are differences between the immune systems of children and adults.

The fighting force of our immune system

Our immune system is designed to protect our body − both inside and out − from infectious bacteria and viruses. It does this through a complex system of specialized warrior cells that patrol the body, destroying invading pathogens. Like well-trained soldiers, these warrior cells attack the pathogens and leave the body’s own cells alone. But, as in any type of warfare, things can go wrong. In some instances, the immune system goes into overdrive when fighting off a COVID-19 infection, attacking healthy cells in the process and leading to severe cases of the disease.

How a child’s immune system differs from that of an adult

Some of the most important immune cells are memory T cells, which learn to recognize pathogens that they encounter over a lifetime. One theory suggests that one reason children can neutralize the virus is that their T cells are relatively naïve, compared to an adult’s. This means that they do not have any specificity or preference for the pathogen causing the infection. Because children’s T cells are mostly untrained, they may have a greater capacity to respond to new viruses and mount a quick and effective response. Science is studying this phenomenon in more detail.

Meanwhile, there is evidence that children’s noses have lower levels of the ACE2 receptor that allows the virus to gain access to cells. Because their noses contain fewer receptors, they may receive a smaller dose than adults, should they contract the virus. Researchers also think that this may explain why COVID-19 is less common in children than adults.

Children can still have a severe reaction to the virus

Children who are immunocompromised − with conditions such as lupus or juvenile rheumatoid arthritis − have overactive immune systems, which puts them at increased risk for more severe cases of COVID-19. As well, a small percentage of infected children will develop a serious inflammatory condition called MIS-C following the infection. This can result in inflammation of various organs such as the heart, lungs and brain. While there have been some deaths, most children will recover under a doctor’s care.

Can kids spread COVID-19?

Experts are still debating this. Studies during the early days of the pandemic suggested that children did not substantially contribute to the spread of the virus, but that idea is now being questioned.

Recent studies show that infected children had as much, or more, coronavirus in their upper respiratory tracts as did infected adults. While this did not definitively prove that children are infectious, the presence of high viral loads in infected children did suggest that children, even without symptoms, could readily transmit the infection to others.

Where we’re at with vaccines and children

What scientists do know is that we need a safe and effective vaccine for children…ASAP. And researchers are working on it. Most of the vaccines developed for COVID-19 focus on the spike protein found on the surface of the coronavirus that is responsible for the infection. When vaccinated, the body produces antibodies to the spike protein, so that if a person gets infected, the immune cells recognize the spike protein as something foreign and attacks it.

Vaccines for children trigger the same immune response as in adults. While the subject is a controversial one with vaccine skeptics, vaccinating children will be critical to achieving a population-wide herd immunity, the point at which the spread of an infectious disease slows down, and eventually halts as it runs out of hosts to infect.

There are four authorized vaccines for COVID-19 in Canada, all proving to be nearly as effective in the real world as they were in clinical trials.

In May, Canada approved the use of the Pfizer BioNTech COVID-19 vaccine for adolescents 12-15 years old. As of the date of this writing, this is the only vaccine authorized in Canada for anyone under age 18. Additionally, Moderna says that its vaccine is effective in adolescents and it plans to apply for F.D.A. authorization.

In the meantime, there are ongoing trials to determine vaccine safety and efficacy in younger children.

Which companies are testing a vaccine for younger children?

Moderna’s newest trial – KidCOVE − will test two- and three-dose levels in children aged six months to younger than 12 years. Moderna plans to enrol about 6,750 children in the U.S. and Canada for this trial, with some children getting the vaccine and others a placebo.

Similarly, in March of this year, Pfizer and BioNTech announced plans to start a study to further evaluate the safety, tolerability and immunogenicity of the Pfizer-BioNTech COVID-19 vaccine in children aged six months to 11 years.

Figuring out the right doses for younger children is important. For vaccines, children usually receive the same doses as adults. However, because children sometimes have a more robust immune response to vaccines, they may need a lower dose. Information on side-effects will be collected as the trials continue. Findings from these studies will also help experts decide whether children will need boosters of COVID-19 vaccines in the future.

No kidding around when it comes to safety

As we enter the second summer of the pandemic, all of us are longing to return to some semblance of normalcy − especially for our children. While they may not get seriously ill with COVID-19, lockdowns are taking their toll on children’s mental health. As with adults, physical activity is critical for kids, whether it’s an organized sport, in-line skating or walking outdoors with friends and family. Given that children younger than 12 cannot yet be vaccinated, what should families with young children do when people start socializing again?

There is no single answer. For many, it will depend on the number of COVID-19 cases in their community, and the latest data regarding local infection rates, COVID-19 hospitalization statistics or vaccination rates. Others will have to weigh the risks of prolonged social isolation against going to public places, where they’re not certain whether or not unmasked people are vaccinated.

For now, it may be challenging to let kids be kids − but it is possible with the right precautions.

Playing It Safe This SummerCDC (Centers for Disease Control and Prevention) research has shown that schools have not been a major source of transmission, but the same doesn’t apply to extracurricular activities. Unmasked activities among children should be limited to outdoor settings. Children should be masked when taking part in indoor group activities.Additionally, the CDC has directed everyone attending summer camp this year to wear a mask at almost all times. This applies to counselors and campers, whether they are vaccinated or not.For many sports, such as tennis or volleyball, there is a low risk of transmission when playing outdoors unmasked. However, that risk of transmission goes up for contact sports such as rugby and basketball.Attending a concert or baseball game in an undomed stadium is considered fairly safe for vaccinated people. However, stadiums with domes or roofs can trap air, which can increase the risk of viral spread.Exercise caution around crowds of strangers who are not wearing masks, such as on a crowded beach, for example. Ask your children to wear a mask when they are with other unvaccinated people and keep their distance while eating.Keep children’s outdoor parties small (fewer than 10 children) and hold them in a park or big yard, if possible. If there is a need to go inside, keep the windows open for air circulation.For travel, check local vaccination rates and surges in infection rates for your proposed destination. Studies show that your risk of getting COVID-19 is lower in places where the number of vaccinated people has reached about 60-70 per cent.Air travel is fairly safe, assuming that everyone is masked. But, since the risk of transmission goes up the longer the flight, consider double masking and limiting the number of flights.If grandparents have been vaccinated fully for two weeks, then it’s considered safe to hug their grandchildren again.

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