Pfizer, Moderna boosters less effective at 4 months, but protect against hospitalization
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mRNA COVID-19 vaccine boosters from Pfizer (PFE
-0.5%)/BioNTech (BNTX
+1.6%) and Moderna (MRNA
+1.4%) become less effective after four months, but still provide significant protection against hospitalization, a CDC study found.
While vaccine efficacy was still strong two months after a booster shot, it declined significantly after four months.

Efficacy against emergency department visits and hospitalization was, respectively, 87% and 91%, after two months. After four months, those figures dropped to, respectively, 66% and 78%.
Researchers said the results suggest that additional boosters may be needed.
"The finding that protection conferred by mRNA vaccines waned in the months after receipt of a third vaccine dose reinforces the importance of further consideration of additional doses to sustain or improve protection against COVID-19âassociated ED/UC encounters and COVID-19 hospitalizations," they wrote.
Read why Seeking Alpha contributor Shock Exchange considers Moderna a sell.