Drugmaker Moderna said on Wednesday it would soon start testing its coronavirus vaccine in children aged 12 to 17. The study, listed on clinictrials.gov on Wednesday, is expected to include 3,000 children, half of whom receive two shots of the vaccine four weeks apart. and half receive placebo injections of salt water.
But the publication says the study is “not recruiting yet,” and Colleen Hussey, a spokesperson for Moderna, said it was uncertain whether testing sites would be listed or start accepting volunteers. A link on the website to the testing centers is not yet working, and Ms Hussey said she was unsure when it would become active.
Moderna announced Monday that data from her study of 30,000 adults found her vaccine to be 94.1% effective and that she had applied to the Food and Drug Administration for emergency clearance to begin vaccinating adults. If approval is granted, certain groups of high-risk adults, including people living in nursing homes, could receive vaccines at the end of December.
But no vaccine can be given widely to children until it has been tested in them. Vaccines intended for both adults and children are usually tested first in adults to make sure they are safe for pediatric trials.
Moderna’s vaccine has not yet been studied in children or pregnant women. In the new adolescent clinical trial, girls after puberty will be tested before each injection to make sure they are not pregnant.
“Everyone expects that when we test this first in adolescents, then older children, then real small children, that the Covid vaccine will work,” said disease specialist Dr William Schaffner infectious diseases at Vanderbilt University and vaccine advisor to the Centers for Disaster Control and Prevention.
But children have more active immune systems than adults and may have stronger reactions, including more fever, muscle and joint pain, and fatigue, said Dr Schaffner.
“They can be worse off than adults for a day or two,” he says. “You really want to know, if it’s given to teenagers, what can parents expect? You really want to be able to tell them clearly how you might feel for 24 or 48 hours after getting the vaccine. And obviously we really want to be able to tell parents that it works.
If a child had intense side effects and parents weren’t prepared for it, they might be reluctant to come back for the second shot, Dr Schaffner said.
Dr Paul A. Offit, a vaccine expert at Children’s Hospital in Philadelphia, said vaccines “for the most part” work just as well in children as they do in adults. Sometimes, like with the hepatitis B vaccine, different doses are needed, he said. Moderna will study the same dose in children as it has tested in adults.
Confused by all of the technical terms used to describe how vaccines work and are studied? Let us help you:
- Adverse event: A health problem that arises in volunteers during a clinical trial of a vaccine or drug. An adverse event is not always caused by the treatment tested in the trial.
- Antibody: A protein produced by the immune system that can attach to a pathogen such as coronavirus and prevent it from infecting cells.
- Emergency use approval, license and authorization: Medicines, vaccines and medical devices cannot be sold in the United States without winning approval of the Food and Drug Administration, also known as license to practice. After a company submits clinical trial results to the FDA for review, the agency decides whether the product is safe and effective, a process that typically takes several months. If the country faces an emergency – such as a pandemic – a business may instead request a emergency use authorization, which can be granted much faster.
- Background rate: How often a health problem, called an adverse event, occurs in the general population. To determine whether a vaccine or drug is safe, researchers compare the rate of adverse events in a trial to the baseline rate.
- Efficiency: A measure of the effectiveness of a treatment in a clinical trial. To test a vaccine against the coronavirus, for example, researchers compare the number of people in the vaccinated and placebo groups receiving Covid-19. The actual effectiveness of a vaccine may be different from its effectiveness in a trial.
- Phase 1, 2 and 3 trials: Clinical trials generally take place in three stages. Phase 1 trials typically involve a few dozen people and are designed to observe whether a vaccine or drug is safe. Phase 2 trials, involving hundreds of people, allow researchers to try different doses and collect more measurements of the vaccine’s effects on the immune system. Phase 3 trials, involving thousands or tens of thousands of volunteers, determine the safety and effectiveness of the vaccine or drug while waiting to see how many people are protected from the disease they are supposed to be fighting for.
- Placebo: A substance with no therapeutic effect, often used in a clinical trial. To see if a vaccine can prevent Covid-19, for example, researchers can inject half of their volunteers with the vaccine, while the other half are given a saltwater placebo. They can then compare the number of people in each group infected.
- Post-market surveillance: The follow-up that takes place after the approval of a vaccine or drug and which is regularly prescribed by doctors. This monitoring usually confirms that the treatment is safe. On rare occasions, it detects side effects in certain groups of people that were missed in clinical trials.
- Preclinical research: Studies that take place before the start of a clinical trial, usually involving experiments where a treatment is tested in cells or in animals.
- Viral vector vaccines: A type of vaccine that uses a harmless virus to introduce immune system boosting ingredients into the human body. Viral vectors are used in several experimental Covid-19 vaccines, including those developed by AstraZeneca and Johnson & Johnson. Both companies use a cold virus called adenovirus as a vector. The adenovirus carries coronavirus genes.
- Test protocol: A series of procedures to be performed during a clinical trial.
Pfizer began testing its coronavirus vaccine in children as young as 12 in October. A large clinical trial found its vaccine to be 95% effective in adults, and the company requested emergency clearance from the FDA, Britain on Wednesday approved the Pfizer vaccine for adults, the first country to do so .
AstraZeneca has also tested its vaccine in children, but not in the United States.
As vaccine studies have progressed, rumors have spread on social media, especially among people who oppose vaccines in general, that President-elect Joseph R. Biden Jr. plans to ” require vaccination for everyone, including children. His team has denied the claims and Mr Biden said he would rely on the advice of scientists to find the best way to end the pandemic.