The Moderna-Covid-19 vaccine and an experimental protein-based preventive agent were shown to be safe in a study on baby rhesus monkeys and showed a good antibody response to SARS-CoV-2, scientists say.
The study, published Tuesday in the journal Science Immunology, suggests that vaccines for young children are likely to be important and safe tools in containing the pandemic.
“Safe and effective vaccines for young children will help limit the spread of Covid-19 as we know that children can pass the virus on to others, whether they have SARS-CoV-2 infection or are asymptomatic stay, ”said Sallie Permar from New York – Komansky Presbyterian Children’s Hospital, USA.
“In addition, many children became ill and even died of the infection, and many more are negatively affected by the measures taken to contain the spread. Therefore, young children deserve protection from Covid-19, ”said Permer.
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The strong neutralizing antibody response elicited by the vaccines in 16 baby rhesus monkeys lasted for 22 weeks.
Researchers are running challenge studies this year to better understand the potential long-term protection of vaccines.
“The levels of strong antibodies we observed were similar to those seen in adult macaques, even though the doses were 30 micrograms instead of the 100 microgram adult dose,” said Kristina De Paris, professor at the University of North Carolina. UNITED STATES.
“With the Moderna vaccine, we also observed specific strong T-cell responses that we know are important in limiting the severity of the disease,” said De Paris.
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The researchers immunized two groups of eight small rhesus monkeys at 2.2 months of age and four weeks later.
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), USA.
The mRNA vaccine instructs the body to make the virus’ surface protein called spike protein.
The vaccine instructs the cells to make the spike protein that the virus uses to infect and invade human cells.
The human immune cells recognize the protein and develop antibodies and other immune responses.
NIAID’s vaccine is the actual spike protein itself, which the immune system recognizes in the same way.
Both vaccines elicited high levels of IgG-neutralizing antibodies to SARS-CoV-2 and spike protein-specific T-cell responses, the researchers said.
The vaccines did not elicit T-helper type 2 responses, which can be detrimental to the vaccine’s effectiveness and safety in infants, they said.
Because such reactions can counteract the immune response to the virus, the researchers said, T-helper-2 reactions have hampered vaccine development in young children.
“We were sure we were looking for evidence of T-helper-2 responses such as IL4 in the blood plasma of all macaques to make sure that none of the vaccines produced such a response,” said De Paris.
“We need to study this further, but so far we haven’t seen any evidence of it,” she added.
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