Protection by a Fourth Dose of BNT162b2 against Omicron in Israel

https://www.nejm.org/doi/full/10.1056...

January 2, 2022, Israel, fourth dose of BNT162b2 to over 60s

Effect on infection and severe coronavirus disease

METHODS

Israeli Ministry of Health database

1,252,331 over 60s eligible for the fourth dose

Omicron predominant, (January 10 through March 2, 2022)

Confirmed infection and severe Covid-19

Starting at 8 days after receipt of a fourth dose, (four-dose group)

Compared with (three-dose group)

Received a fourth dose 3 to 7 days earlier (internal control group)

RESULTS

Number of cases of severe Covid-19 per 100,000 person-days

Four dose group, 1.5
Three dose group, 3.9
Internal control group, 4.2

Adjusted rate of severe Covid-19

January 10, 2022, to March 2, 2022

In the fourth week after receipt of the fourth dose

Four dose group, lower than that in the three-dose group by a factor of 3.5

Four dose group, lower than that in the internal control group by a factor of 2.3

Protection against severe illness did not wane during the 6 weeks after receipt of the fourth dose.

The number of cases of confirmed infection per 100,000 person-days (unadjusted rate)

Four dose group, 177

Three dose group, 361

Internal control group, 388

Confirmed infection in the fourth week

January 10, 2022, to March 2, 2022

Four dose group, lower than that in the three-dose group by a factor of 2.0

Four dose group, lower than that in the internal control group by a factor of 1.8

However, this protection waned in later weeks.

CONCLUSIONS

Rates of confirmed SARS-CoV-2 infection and severe Covid-19 were lower after a fourth dose of BNT162b2 vaccine than after only three doses.

Protection against confirmed infection appeared short-lived, whereas protection against severe illness did not wane during the study period.

We excluded the following persons from the analysis

those who had had a confirmed SARS-CoV-2 infection before the beginning of the study,

So this tells us nothing about the effect of natural immunity

Please can we have data on vaccine induced immunity

versus natural infection induced immunity

AND

Efficacy of fourth dose versus two or three dose hybrid immunity