COVID-19 Vaccines for Young Children: The Next Step When Trial Results Are in

Deciding to vaccinate the under-12s means weighing the risks of vaccination for some, against the probably greater risks of infection.

Two doses of the Moderna and Pfizer COVID-19 vaccines are about 95% effective and have few side effects in adults. Now it’s time to consider vaccinating children under 12. But, first, we need to evaluate possible short- or long-term effects of the vaccines.

In Austria, just over 9% of the total COVID-19 cases were in children under 14 years old. 

To date, there was a total of 8,466 cases in children under 5 (boys 4,478 / girls 3,988), and 51,614 (boys 27,012 / girls 24,602) between 5 and 14. We were lucky: Only a small number were hospitalized, and none of them died.  

Many experts argue that we shouldn’t bother vaccinating children under 12 years old. Their arguments are two fold: Firstly, they reason that most children are asymptomatic or have mild symptoms and recover quickly. Secondly, we need a massive supply of vaccines for the millions of unvaccinated adults around the world and that this should be our priority. 

The opposing view in favor of vaccination is that children are the largest unvaccinated population, and we only need one such population to generate global variants that keep the pandemic going.

Childhood vaccines are safe

Childhood vaccinations are routine and widely accepted in most countries to ward off diseases like measles, mumps, polio, diphtheria, rotavirus, meningitis, and whooping cough. Childhood vaccines have few side effects and often induce lifelong immunity. We have a lot of positive experience with vaccines in children and most experts predict that COVID-19 vaccines will also be safe and effective.

Pro: Herd immunity and priority conditions

Supporters argue that vaccinating children against COVID-19 would be another crucial step toward ending the pandemic. The risk is that any population of unvaccinated people, including children, will increase the risk of new viral mutations like the Delta variant. Having more contagious new variants can increase viral spreading and the frequency of severe illness induced with fewer virus particles. At the beginning of the pandemic, a child would only get sick with exposed to a high number of infectious viruses. 

There are additional reasons for vaccinating children. 

Although young children are less likely to become severely ill, there’s still a chance that some will get sick and die. But that’s not all – there will be more cases of the post-COVID-19 multisystem inflammatory syndrome (MIS-C) with possible heart, gastrointestinal and neurological problems. There’s also an increased risk of ‘long-term COVID-19’ in children – even after a mild episode – that could last for months and possibly years.

Another problem is the potential risk of severe illness if COVID-19 combines with other common viruses, like respiratory syncytial virus (RSV), which can cause severe respiratory disease. There will likely be more cases of RSV as precautions ease, leading to co-infection with SARS-CoV-2 and possibly, even more severe disease.

Vaccines protect children and those around them. Even when children are asymptomatic, they can spread COVID-19 to unvaccinated adults. So, children who live with vulnerable adults and those with suppressed immune systems should be vaccinated to protect the broader community’s health from the more transmissible Delta variant (and others). 

The more unvaccinated children and adults, the more SARS-CoV-2 infections, the more opportunities the virus has to mutate and potentially resist current vaccines and therapies.

The bottom line, this argument goes, is that vaccinating children is essential for herd immunity.

It’s important to first vaccinate children with underlying health problems that increase their risk of getting severely ill with COVID-19, e.g., asthma, diabetes, some cancers, immunosuppression or a weakened immune system, and possibly children with cerebral palsy, autism, epilepsy, and Down’s syndrome.

Contra: Rare complications and allergies

Currently, the youngest vaccinated group are adolescents, and the good news is that the RNA vaccines appear to be safe for them. 

The most common side effects are similar to adults, with pain, redness and swelling at the injection site, fatigue, headache, muscle and joint pain, chills, nausea and fever that lasts for a short time. 

However, there is a rare complication after the second dose of the RNA vaccine that occurs primarily in adolescent boys. They develop pericarditis or myocarditis, which is inflammation around or within the heart. The symptoms are chest pain, shortness of breath, or feelings of having a fast-beating, fluttering or pounding heartbeat. Although most cases have been mild and resolve themselves quickly, with most affected people making a full recovery, it’s essential to figure out whether this will also affect younger children. 

Some children should clearly be excluded, including any with a history of severe allergic reaction to a vaccine or to any medication related to the ingredients in the RNA vaccines (e.g., polyethylene glycol/PEG).  And of course, all children who contracted myocarditis or pericarditis after a first vaccine dose.

Another argument is that other people, including more vulnerable populations globally, need vaccines more.

Challenges: Dosages and detailed trials

So far, authorization for Moderna and Pfizer RNA vaccines has been given for children aged 12 to 15, but clinical trials in children as young as six months old are underway. Until we see the results of vaccine effectiveness and safety studies, we ought to wait. 

There are some hurdles with approving vaccines for children. For example, we need to determine dosages. Typically, vaccine doses are lower for children, which makes them potentially less effective but also reduces the side effects. 

Other challenges are that the numbers of children in any trials need to be high to observe the rare adverse effects, and these studies take longer because of a necessary longer follow-up time (e.g., two years).

Keeping unvaccinated children safe

Unvaccinated children need to be protected, primarily because of more contagious and pathogenic variants. Until vaccines are available, keep your children safe by having them wear masks indoors, physical distance, and wash their hands. They should be routinely COVID-19 tested and should avoid people with COVID-19 and vulnerable unvaccinated adults. 

The benefits must outweigh the risks

We need to evaluate the benefits and risks before vaccinating children under 12. As soon as positive clinical trial results are available, we should vaccinate children, because of concerns over a potential new waves that coincide with the coming school year and the cooler weather that will mean spending more time indoors.

Dr. Michelle Epstein
Michelle Epstein is a medical doctor graduated from the University of Alberta in Canada, who has specialised in Internal Medicine at the University of British Columbia and Allergy and Clinical Immunology at Yale University. Since 2004, she has been a Lab Leader at the Medical University of Vienna’s Division of Immunology.

Current Status

If you live in Vienna, make sure to register for getting a vaccine against COVID-19 under  Here you can book your vaccination appointment.

The City of Vienna offers free vaccinations without an appointment to everyone – regardless of citizenship or insurance status – at multiple locations across the city. 

Vienna has reinstated a number of coronavirus restrictions for the fall. The Austrian government has presented a plan for schools and universities.  

Here’s an overview of where you can get tested for COVID-19 in Vienna and how the free PCR “gargle” tests at home work. 

If everything is a bit much for you or you experience domestic violence of any kind, here is our mental health resource article.


For current coronavirus numbers, check the website of Ministry of Health and the AGES dashboard.

The Austrian Ministry of Health also publishes daily vaccination statistics and a preview of scheduled deliveries.


The City of Vienna has compiled comprehensive information on questions and answers regarding coronavirus and the COVID-19 disease in English.

The Austrian Ministry of Health has put together FAQs on the coronavirus and also provides material to download on how to protect yourself and others from the disease, also in English.

Furthermore, the ministry will constantly update its German-language website with information on the number of people tested and cases of COVID-19 in Austria.


Health advice by telephone1450

If you show symptoms (fever, cough, shortness of breath, breathing difficulties) or fear that you are ill, stay at home and dial health number 1450 for further procedures (diagnostic clarification).

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The Austrian Agency for Health and Food Safety (AGES) answers questions about the coronavirus (general information on transmission, symptoms, prevention) 24 hours a day at +43 0800 555 621.

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