Since the Covid vaccination campaigns started worldwide, studies have been made to see how effective different vaccines are against the different SARS-CoV-2 strains. For now, the most aggressive strain is Delta, which originated in India. This strain is highly transmissible, and it is already the dominant strain in several countries, including the U.S. Most Covid-19 vaccines require two doses for a person to be considered fully vaccinates. Pfizer-BioNTech is even considering a third booster shot for people with weaker immune systems. Scientists are trying to determine what the best time gap between the first and second dose is. By identifying the best time gap, the immune system will produce more antibodies to fight against aggressive strains such as Delta.
A longer gap between Pfizer doses is better
Recent studies show that the initial gap (approx. 3 weeks) between the first and second doses of the Pfizer-BioNTech vaccine should be longer. The U.K has already decided to extend the gap between the two doses, and experts agree. The article also mentions that several factors have been taken into considerations, including the effectiveness of the vaccine in the different age groups. It seems that the research shows that the Pfizer vaccine is most effective if there is at least an eight weeks gap between the doses.
Why is the vaccine more effective with a longer gap between doses?
The study’s chief investigator explains that although results indicate that even one dose is enough for our body to form antibodies, the timing of the second dose is quite important. The study analyzed the number of antibodies of those who got the second shot after three weeks and antibodies of those who waited for more for the second shot. Tests show that a longer gap generates more antibodies.