Business Insider posted an article on Moderna.
Moderna Vs Pfizer Charts: Moderna Vaccine May Not Need Boosters As Much
>>Last week, the Centers for Disease Control and Prevention released data sets from hospitals around the country. That data is starting to indicate that people who got Moderna's vaccine are less likely to be hospitalized than people who got Pfizer's or Johnson & Johnson's.<<
One suggested reason from the article.
>>Moderna's shot consists of 100 micrograms of mRNA vaccine, while Pfizer's has 30 micrograms. That may mean lighter side effects for Pfizer's shot but in the long run, the protection might not be as strong.<<
The other possible reason is dose spacing. Pfizer being 3 weeks, Moderna 4 weeks. The UK used even longer spacing, up to 12 weeks and it seems to matter.