Two COVID-19 vaccines show promising results for young children in early trials: Study

Scientists across the world are studying the efficacy of various COVID vaccines on children as multiple candidates are under clinical trials. In a recent development, scientists have said that the Moderna COVID-19 vaccine and an experimental protein-based preventive proved to be safe and showed a good antibody response against SARS-CoV-2 in a trial on baby rhesus macaques. 

The research, published on Tuesday in the journal Science Immunology, suggests that vaccines for young children are likely important, safe tools to curtail the pandemic.

Sallie Permar from New York-Presbyterian Komansky Children's Hospital, US, said, "Safe and effective vaccines for young children will help limit the spread of COVID-19 because we know children can transmit the virus to others, whether they get sick from SARS-CoV-2 infection or remain asymptomatic".

Permer added, "Moreover, many children have become sick and even died from the infection, with many more negatively impacted by the measures put in place to curb the spread. Thus, young children deserve protection from COVID".

Research analysis

The strong neutralising antibody response elicited by the vaccines persisted for 22 weeks in 16 baby rhesus macaques persisted for 22 weeks. This year, the researchers are conducting challenge studies to better understand the potential long-lasting protection of the vaccines.

Kristina De Paris, professor at the University of North Carolina, US, said, "The level of potent antibodies we observed were comparable to what has been seen in adult macaques, even though the doses were 30 micrograms instead of the 100 microgram adult doses". She further informed, "With the Moderna vaccine, we observed specific strong T cell responses, as well, which we know are important to limiting disease severity".

Two groups of 8 infant rhesus macaques were immunised at 2.2 months of age and four weeks later by the researchers. Each animal received either a preclinical version of the Moderna mRNA vaccine or a protein-based vaccine developed by the National Institute of Allergy and Infectious Diseases (NIAID), US.

The mRNA vaccine delivers instructions to the body to produce the virus's surface protein, the spike protein. The vaccine instructs the cells to create the spike protein, which the virus uses to infect and enter the human cells. The human immune cells recognise the protein and develop antibodies and other immune responses. NIAID's vaccine is the actual spike protein itself, which the immune system recognises in the same manner.

The researchers said that both vaccines elicited a high magnitude of IgG neutralising antibodies against SARS-CoV-2 and spike protein-specific T cell responses. The vaccines did not elicit T helper type 2 responses, which can be detrimental to vaccine efficacy and safety in infants.

The researchers added that since such responses can counter the immune response against the virus, T helper 2 responses have hindered the development of vaccines in young children.

De Paris informed, "We were sure to check for evidence of T helper 2 responses, such as IL4, in the blood plasma of all macaques to be sure neither vaccine produced such a response". She said, "We need to keep studying this, but so far we have seen no evidence of this".

Pfizer COVID Vaccine for Children

On May 10, the FDA issued Emergency Use Authorization for the Pfizer and BioNTech SE COVID-19 vaccine to be given to children ages 12 to 15. It was announced with an objective to vaccinate the majority of children and protect them from the virus. 

(Image credit: UNSPLASH/PTI)