Oxford-Led Study Shows Efficacy Of COVID-19 Vaccines Dwindles Over Time Against Delta Variant

COVID-19 vaccines from Pfizer Inc PFE - BioNTech SE BNTX and Oxford–AstraZeneca Plc AZN have shown effectiveness against the highly infectious Delta variant of SARS-CoV-2.
But the protection drops away over time, a study in the U.K. has concluded.
Researchers analyzed a data set comprising the results of more than 2.6 million PCR tests.
The results, published in a preprint on 19 August, suggest that both vaccines are effective against Delta after two doses but that the protection they offer wanes with time.
Pfizer-BioNTech's vaccine was 92% effective at keeping people from developing a high viral load 14 days after the second dose. But the vaccine's effectiveness fell to 90%, 85%, and 78% after 30, 60, and 90 days, respectively.
Oxford-AstraZeneca shot was 69% effective against a high viral load 14 days after the second dose, falling to 61% by 90 days.
The data also suggest that the time between doses of vaccine doesn't affect vaccine effectiveness.
Related: Do mRNA COVID-19 Vaccines Cause Skin Or Kidney Disorders? EMA Investigates Possible Links.
Price Action: PFE shares are up 0.94% at $49.26, BNTX stock is up 6.77% at $354.27, AZN stock is up 0.50% at $59.49 during the market session on the last check Friday.
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