Heterologous Boosters

[M_T]

Another study caught my eye regarding heterologous vs homologous boosters.
Association of Homologous and Heterologous Vaccine Boosters With COVID-19 Incidence and Severity in Singapore

Among individuals who received BNT162b2 [Pfizer] for their primary series, the incidences (per million person-days) of confirmed and severe infections were 227.9 and 1.4 for homologous-boosted
compared with 600.4 and 20.5 for nonboosted individuals. The IRRs were 0.272 (95% CI, 0.258-0.286) for the confirmed cases among homologous-boosted individuals and 0.047 (95% CI, 0.026-0.084) for severe cases.
For heterologous-boosted individuals, the incidences of confirmed and severe infections were 147.9 and 2.3 cases per million person-days, respectively, with IRRs of 0.177 (95% CI, 0.138-0.227) and 0.078 (95% CI, 0.011-0.560).

For individuals who received mRNA-1273 [Moderna] for their primary series, the incidence of confirmed infections for homologous-boosted individuals was 133.9 cases per million person-days (IRR, 0.198 [95% CI, 0.144-0.271]). For heterologous-boosted individuals, the incidence of confirmed infections was 100.6 per million person-days (IRR, 0.140 [95% CI, 0.052-0.376]). The number of severe infections among individuals receiving mRNA-1273 for their primary series was too small to assess IRRs.

The boosters were the same as in the US  (Pfizer: 30µg,  Moderna 50µg)

Note they used person-days at risk, avoiding one of my concerns about studies in earlier posts.

Ok, this is just one study, but it makes me feel that I nailed it.  I am in the group of initial Moderna, with a heterologous booster.