Two vaccines, the vaccine Moderna mRNA and a compound made from protein has shown its safety and efficacy in a child animal model. In a study published in
Science Immunology, both vaccines elicited long-lasting neutralizing antibody responses to SARS-CoV-2 with no adverse effects.
The research, carried out by researchers from the
University of North Carolina at Chapel Hill, Weill Cornell Medicine Y NewYork-Presbyterian (USA), suggests that vaccines for young children are likely to be important and safe tools to reduce the pandemic.
“Vaccines seem safe and effective for young children and could help limit the spread of Covid-19 since we know that children can transmit the virus,” says Sallie Permar, from the Pediatrics Department from Weill Cornell.
The study confirms strong neutralizing antibody responses elicited by vaccines in 16 baby rhesus macaques that persisted for 22 weeks. Researchers are conducting studies to better understand the possible lasting protection of vaccines.
‘The level of potent antibodies that we observed was comparable to what has been seen in adult macaques, even though the doses were lower (30 micrograms instead of the 100 microgram doses for adults) ”, explains Kristina De Paris, author of the study.
“With the Moderna vaccine, we also see strong responses T cell specific, which we know are important to limit the severity of the disease.
To evaluate childhood vaccination against SARS-CoV-2, the researchers immunized to two groups of 8 baby rhesus macaques at 2.2 months of age and 4 weeks later in the California National Primate Research Center.
Each animal received one of two types of vaccines: a preclinical version of Moderna’s mRNA vaccine or a protein-based vaccine developed by him.
Center for Vaccine Research of the National Institute of Allergy and Infectious Diseases (NIAID) USA, part of the National Institutes of Health, with a 3M adjuvant that stimulates cells through receptors 7 and 8. The adjuvant was formulated in an emulsion by the Infectious Diseases Research Institute (IDRI).
The mRNA vaccine it’s like a message, the researchers explain; delivery instructions to the body to produce the virus’s surface protein, the spike protein. The vaccine does not enter the nucleus, it does not affect its DNA, and it does not persist in the body. Instead, it teaches cells to create spike protein and, thus, our immune cells will recognize it, developing antibodies and other immune responses.
NIAID is the spike protein itself, which the immune system recognizes in the same way. It is similar to the protein-based vaccine Novavax, which reports indicate is highly effective and safe.
Both vaccines caused a high magnitude of neutralizing IgG antibodies against SARS-CoV-2 and the specific T cell responses of the protein Spike -IL-17, interferon-g and TNF. These are called T helper 1 immune responses.
Importantly, the vaccines did not elicit responses T helper tipo 2, which can be detrimental to the efficacy and safety of the vaccine in infants. These responses can counteract the immune response against the virus. And so T helper 2 responses have hampered vaccine development in young children, especially for common respiratory syncytial virus (RSV).
“We were sure to check for evidence of T helper 2 responses, such as IL4, in the blood plasma of all macaques to make sure that no vaccine produced such a response,” says De Paris.