A recent study from Scotland reveals that one (1) dose of the COVID-19 vaccine confers roughly the same protection as two (2) doses when measuring the efficacy after allowing for a similar amount of time for immunity to develop. TrialSite’s been on the record that in the case of the mRNA-based vaccine,s perhaps Board Room revenue decision making trumped healthcare. In a recent correspondence piece in The Lancet, the authors share, “Overall, a strong vaccine effect did not clearly manifest until at least 28 days after the first vaccine dose (HR 0·32, 95% CI 0·22–0·46; appendix p 3). Among S gene-negative cases, the effect of vaccination (at least 28 days after first or second dose) was to reduce the risk of hospital admission (HR 0·28, 95% CI 0·18–0·43) compared to unvaccinated.”
Herein, the authors fail to state exactly what measure of vaccine effect they are quoting for the single dose. Are they referring to symptomatic infection, hospitalization, or other? However, when probing the Supplemental document, one can read the details more clearly. Refer to Table S2 where the authors list the hazard ratios for various dosing regimens and time offsets. The two that represent the fairest assessment of 1 dose vs 2 doses are highlighted below. v1_28+ stands for 1 dose-measuring efficacy starting at 28 days. v2_14+ represents two doses measuring efficacy starting 14 days after the second dose. This is a minimum of 35 days but in the UK with their delayed second dose approach (12 weeks), it’s typically a much longer interval (up to 98 days). Therefore, the 2 dose regimen is still offered greater duration for immunity to develop through well-established processes such as affinity maturation. However, even with the shorter time allowed for the single dose to develop immunity, the Hazard Ratios are almost the same at 0.32 vs 0.30 for 1 dose vs 2 dose.
Here is a link to the Supplemental Data that contains the above table. This study was looking at the UK (Alpha) variant and Wildtype. While the Delta variant would likely show a small reduction in vaccine efficacy, the reduction would be similar for the single and double-dose regimens. This study also looked at both the AstraZeneca/Oxford and Pfizer vaccines. That’s the reason the blended HRs are not as impressive as what you’d expect in a purely mRNA vaccine study.
TrialSite suggests regulatory agencies start reviewing the data without the bias favoring the second jab, and its lengthier duration for established immunity. What if it turned out done dose of the mRNA-based vaccines would suffice? We predict far fewer safety reports uploaded to VAERS, although according to the government, the data in VAERS isn’t proven to be associated with the vaccines.