“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,” said Kristina De Paris, PhD, professor of microbiology and immunology at the UNC School of Medicine.

“With the Moderna vaccine, we observed specific strong T cell responses, as well, which we know are important to limiting disease severity,” De Paris added.

Researchers immunised two groups of 8 infant rhesus macaques at 2.2 months of age and 4 weeks later. Each animal received one of two vaccine types, with an adjuvant from 3M that stimulates cells through toll-like receptor 7 and 8.

Both vaccines produced high magnitude of IgG neutralizing antibodies against SARS-CoV-2 and Spike protein-specific T cell responses -IL-17, IFN-g, and TNF. These are called T helper 1 immune responses.

The vaccines did not elicit T helper type 2 responses, which can be detrimental to vaccine efficacy and safety in infants. Such responses can counter the immune response against the virus.

And so, T helper 2 responses have hindered the development of vaccines in young children, most notably for the common Respiratory Syncytial Virus (RSV).

Source: Medindia