Pharmaceutical company Pfizer on Wednesday said its vaccine for kids under age 5 produced 93 percent of immune responses in a clinical trial, a surprise to its researchers and giving it cause for optimism about its prospects.
Called COVID-19, the vaccine has been studied since 2013 but has not yet been submitted for approval in the United States, Europe or Canada. The results published in the New England Journal of Medicine on Wednesday represent the first evidence of its efficacy.
Children who took COVID-19 for 13 weeks were 91 percent effective in preventing or delaying the onset of an infection like influenza, compared with an 81 percent rate for another vaccine developed and licensed by other companies, the Vaccine Research Institute for Infectious Diseases, or VIRICAN, said in a statement.
VIRICAN said the data suggest that COVID-19 is superior to its own “brand” vaccine, but that it will need to perform better in another trial before its benefit is seen. “Even a small and successful outcome for COVID-19 could have an important impact on global influenza-prevention efforts,” VIRICAN said.
Patients were randomized to take COVID-19 or a placebo; 80 percent of the placebo group developed influenza in the vaccine-taking group, compared with 17 percent among the children in the placebo group who received COVID-19. The responses were maintained after several months of follow-up.
VIRICAN said it published the data in the journal to help focus attention on COVID-19 in preparation for the next phase of its study, which should occur this winter.
There is strong reason to believe that COVID-19 could outperform the other vaccines. Early trials of COVID-19 were conducted on infants and toddlers whose immune systems were still immature. Research has shown that vaccines formulated for these early-stage infants work better than vaccines to guard against infections experienced later in childhood.
In a statement, VIRICAN said it’s an early start in its research, given the number of children and parents who would have to be involved to test COVID-19 on a larger number of people. “The success and potential of the COVID-19 vaccine will depend on more than just its performance in small groups of children,” VIRICAN said.
Pfizer said COVID-19 is a regular influenza vaccine that activates the body’s natural defense system, including the immune system’s T cells, antibodies and destroyers of influenza-causing viruses. The C difficile cause of deaths associated with the vaccine is not known.
For the current trial, COVID-19 was compared with NVIVIA, developed by Novartis and licensed in the United States in 2016. Earlier clinical studies of NVIVIA have been positive, although some have expressed concern about its safety.
Pfizer’s COVID-19 also is being studied against a rival vaccine from TSK, owned by the Japanese conglomerate Takeda Pharmaceutical, and has received a licence from the European Medicines Agency for that purpose.