Moderna says its bivalent vaccine, the updated version of the COVID-19 booster vaccine, provides effective protection against the Omicron subvariants BA.4 and BA.5.

In a press release, Moderna said its bivalent mRNA vaccine was developed to target the original Omicron variant and the initial COVID-19 strain in a single dose.

It added, "One month after administration to previously vaccinated and boosted participants, the 50 [microgram] booster dose led to strong neutralizing antibody responses against the Omicron subvariants BA.4 and BA.5 in all participants regardless of prior infection."

The company noted that the vaccine did not generate as many antibodies as it did against the original Omicron variant despite early promises of protection against both variants.

The company also pointed out that Moderna's prototype third booster dose proved effective against Delta and BA.1 infections.

The bivalent mRNA shot has not yet been licensed in the United States or Canada, but the company hopes to receive approval sometime in the fall.

BA.4 and BA.5 Omicron variants are spreading rapidly in the United States as health experts emphasize the subvariants' ability to weaken immunity and lead to reinfection. There are concerns that BA.4 and BA.5 may cause more severe illness.

In June, Ontario’s Chief Medical Officer of Health said additional booster vaccines will start appearing sometime in the fall.

Dr. Kieran Moore confirmed that Ontario will purchase more than six million doses of flu vaccine and expects to offer additional doses against COVID-19.

Meanwhile, children have actually started receiving vaccinations in the United States after approval from the U.S. Food and Drug Administration.

The FDA gave the green light to the Moderna and Pfizer vaccines for children on Friday.

Earlier in the United States, COVID-19 vaccines were first tested and administered in late 2020 to healthcare workers and the elderly. Adolescents and school-age children were added last year.

In the same context, the Centers for Disease Control and Prevention (CDC) recommend vaccination even for those who have already been infected with COVID-19 to protect against reinfection.

Dr. Pam Zetlin, Director of Pediatrics at National Jewish Health in Denver, said: "Some parents fear the child is younger and may be more susceptible to side effects from the vaccine."

"But that is not what Pfizer and Moderna studies found. The side effects were similar to those observed with other childhood vaccines, including fever, irritation, and fatigue."