Tamandjou et al. (French study): the boosters (second booster or 4th dose) devastating for vaccinee with surge in risk of re-infection; FAR LESS effective than 1st boost, regardless of time points

by Paul Alexander

TOLERANCE again! A problem. The gain in protection offered by the second booster was lower than the protection observed with the first booster, at equal time points since last vaccination.

French researchers sought to assess the effectiveness of the second booster relative to the first booster and the protection conferred by a previous SARS-CoV-2 infection, against symptomatic Omicron BA.2 or BA.4/5.

Key finding:

‘We included symptomatic ≥60 years old individuals tested for SARSCoV-2 in March 21-October 30, 2022. Compared to a 181-210 days old first booster, a second booster restored protection with an effectiveness of 39% [95%CI: 38% - 41%], 7-30 days postvaccination This gain in protection was lower than the one observed with the first booster, at equal time points since vaccination.’

SOURCE:

https://www.medrxiv.org/content/10.1101/2023.01.11.23284137v1.full.pdf

Key finding below (Figure 1):

‘A statistically significant decrease in the rVE, across time intervals since last vaccination, was observed for both booster 1 and booster 2. However, at similar vaccination time points, the gain in protection measured by the rVE offered by the second booster was lower than the protection offered by the first booster. For instance, rVE of the second booster 91-120 days ago was 8% [5% - 10%] whereas at the same time interval, the rVE of the first booster was 33% [32% - 35%] (Figure 1).’

In figure 2 below, ‘compared to people without previous infection, the more recent was the previous infection, the higher was the protection against symptomatic infection (Figure 2). For instance, the adjusted protection associated with a 61-112 days old previous infection which occurred during the Omicron BA.2 dominant period was 95.6% [95.0%–96.1%] whereas a 321-467 days old previous infection from the Delta-predominant period was associated with protection of 61.7% [57.5%–65.5%].’