Over the weekend, Pfizer
Current vaccines used the in the United States were developed to target the original SARS-CoV-2 strain that was first discovered in Wuhan, China in 2019. Since then, the virus has mutated numerous times, with variants like Delta and now Omicron becoming the dominant global strain in the process. While these original vaccine still provide protection against severe disease, hospitalization and death--especially after a third booster dose--their effectiveness against infection has diminished significantly.
Now as Omicron and its even more transmissible sub-variants BA.4 and BA.5 circulate, global health regulators are looking for potential next-gen booster candidates ahead of the fall and winter seasons in effort to prevent another massive wave of infections.
Pfizer studied two different vaccine candidates that update the drugmaker's current vaccine to better protect against Omicron--a standalone Omicron booster shot and a combination vaccine of the Omicron booster than the companies' original vaccine. The company also studied both candidates at two different dosage levels--a standard 30 microgram dose and a 60 microgram dose--to see which amount produced the most viral-neutralizing antibodies.
The company found in its study, which included over 1,200 adults who already received three doses of the Pfizer-BioNTech vaccine, showed that both vaccine candidates produced a strong immune system response, with the solo Omicron booster providing the strongest response.
Pfizer said after a month trial participants who received the combination shot had a 9- to 11-fold increase in Omicron-neutralizing antibodies, while the standalone Omicron booster produced a 13.5- to 19.6-fold response.
"Based on these data, we believe we have two very strong Omicron-adapted candidates that elicit a substantially higher immune response against Omicron than we've seen to date," said Pfizer CEO Albert Bourla in a press statement.
Rival vaccine-maker Moderna
