The Covid-19 vaccine Moderna and an experimental protein-based preventive proved to be reliable and demonstrated good antibody response against coronavirus in a trial on baby rhesus macaques, scientists confirmed.
The research was published on Tuesday in the Science Immunology journal, suggesting that vaccines for young children are important, and safe tools to curb the pandemic.
Sallie Permar from New York-Presbyterian Komansky Children’s Hospital 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.”
Moreover, Permar added that many children got sick and even died due to the virus, with many more negatively affected by the measures placed to curb the spread. “Thus, young children deserve protection from COVID-19,” she noted.
The effective neutralising antibody response obtained by the vaccines in 16 baby rhesus macaques lasted for 22 weeks.
To understand the potential long-lasting protection of the vaccines better this year, the researchers are administering the challenge studies.
University of North Carolina Professor, Kristina De Paris, said the level of potent antibodies they observed was similar to what was seen in adult macaques, even though the doses were 30 micrograms instead of 100 micrograms given to adults.
“With the Moderna vaccine, we observed specific strong T cell responses, as well, which we know are important to limiting disease severity,” she said.
The researchers first immunised two groups of 8 infant rhesus macaques at 2.2 months old and then four weeks later.
Each infant rhesus received either a preclinical variant 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 directs instructions to the body to induce the surface protein of the virus, the spike protein.
The vaccine directs the cells to create the spike protein, from where the virus infects and enters the human cells.
The human immune cells identify these protein and then develop antibodies and other immune responses.
NIAID’s vaccine is the genuine spike protein, which the human immune system recognises in the same way.
The researchers said both vaccines elicited high magnitude of IgG neutralising antibodies against coronavirus and spike protein-specific T cell responses.
They said vaccines did not elicit any T helper type 2 responses, which can harm vaccine efficacy and infant safety.
The researchers said as these responses can hinder the human immune response against the virus, T helper 2 responses have countered the vaccine development in young children.
“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,” Ms. De Paris said. We need to keep studying this, but we have not seen evidence of this so far, she added.
(Inputs from PTI)
