2 doses of the J&J or 2 doses of the Pfizer COVID-19 vaccine? New research out of South Africa reveals they're equally effective against serious illness caused by the Omicron variant.

Looking back two months: Review of the single-dose Johnson & Johnson COVID-19 vaccine's effectiveness against the Beta and Delta variants

In March 2022, prestigious clinical journal, The Lancet published new research emanating from leading South African scientists and co-authored by members of our Health Intelligence Unit at Discovery Health.

This at-scale, real-world study confirmed the high effectiveness of the single-dose Johnson & Johnson (J&J) COVID-19 vaccine against serious illness, during South Africa's second and third wave of infection - driven by the Beta and Delta COVID-19 variants respectively (so, vaccine effectiveness against two distinct variants of concern).

This data reflected on the experience of vaccinated healthcare workers - a highly-exposed group, many of whom live with HIV - who took part in the Sisonke Study (which allowed health care workers early access to the J&J COVID-19 vaccine through an implementation science clinical trial, preceding and bolstering the national vaccination roll out).

Discovery Health provided an integral control group data set to this study.

In summary, this study found the single-dose J&J COVID-19 vaccine to be:

• 83% (95% CI, 75-89%) effective in preventing COVID-19 related deaths
• 75% (95% CI, 69-82%) effective in preventing COVID-19 related hospital admissions requiring critical or intensive care
• 67% (95% CI, 62-71%) effective in preventing COVID-19 related hospitalisations.

Most breakthrough infections in the health-care worker sample group were asymptomatic or mild. Less than 1% of health-care workers had a severe SARS-CoV-2 infection that resulted in hospitalisation or death.

South Africa's changing COVID-19 and vaccination landscape

Starting in October 2021, health care workers who participated in phase 3b of the Sisonke study were eligible to receive a second dose of the J&J COVID-19 vaccine. Thereafter, access to a second dose of the J&J vaccine was opened up to the general public.

• From late February 2022, members of the South African public could have the J&J COVID-19 vaccine as a booster dose 90 days after the second Pfizer vaccine dose or 60 days after a first J&J COVID-19 vaccine dose.

Furthermore, by the end of 2021, South Africa was into its fourth wave of infection, driven by the Omicron variant - which according to the Network for Genomic Surveillance in South Africa, spanned 21 November 2021 to 23 March 2022.

Looking to the present: Review of either a two-dose Johnson & Johnson or two-dose Pfizer COVID-19 vaccine regimen's effectiveness against serious illness caused by the Omicron variant

On 4 May 2022, the New England Journal of Medicine published correspondence to the Editor explaining the findings of one of the first real-world studies on vaccine effectiveness against the B.1.1.529 (Omicron) strain of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).

• Co-authors of the correspondence to the NEJM include leading scientists from the South African Medical Research Council, Discovery Health, Centre for the AIDS Programme of Research in South Africa, The National Department of Health, the National Institute for Communicable Diseases, and the University of Cape Town.

As authors explain, the Omicron strain has rapidly become dominant among variants of concern in all regions of the world. It has also been shown to escape antibody neutralization by both the Pfizer (BNT162b2 messenger RNA vaccine, Pfizer-BioNtech) and J&J (Ad26.COV2.S vaccine / Johnson & Johnson-Janssen) COVID-19 vaccines, which are the only two COVID-19 vaccines that have been administered in South Africa.

Shirley Collie, Chief Healthcare Analytics Actuary, Discovery Health, and lead analyst on the study explains, "The early effectiveness of a two-dose Pfizer vaccine regimen was established during South Africa's Omicron-driven fourth wave. Now the new study we've carried out, using data from Discovery Health, provided vaccine effectiveness estimates of the original two-dose series of the BNT162b2 (Pfizer) vaccine and a second (booster) dose of the Ad26.COV2.S (J&J) vaccine against severe COVID-19 caused by the Omicron variant."

The study analysed the results of 162,637 PCR tests, of which 93,854 (57.7%) had been obtained from participants who had received two doses of the BNT162b2 vaccine given at least 42 days apart or two doses of the Ad26.COV2.S vaccine given 4 to 6 months apart.

• Read the correspondence in full, titled: "Effectiveness of Ad26.COV2.S and BNT162b2 Vaccines against Omicron Variant in South Africa".

Results: Both vaccines (two doses of each) equally effective in protecting against severe disease caused by the Omicron variant

A) Two-dose J&J COVID-19 vaccine:

Effectiveness against hospitalization for COVID-19 was:

• 55% within 13 days after the second dose
• 74% (95% CI, 57 to 84%) at 14 to 27 days
• 72% (95% CI, 59 to 81%) at 1 to 2 months.

Effectiveness against ICU admission or high care was:

• 69% at 14 to 27 days
• 82% (95% CI, 57 to 93%) at 1 to 2 months after the second dose

B) Two-dose Pfizer COVID-19 vaccine:

Effectiveness against hospitalization for COVID-19 was:

• 81% within 13 days after the second dose
• 88% at 14 to 27 days
• 70% (95% CI, 64 to 76%) at 1 to 2 months
• 71% (95% CI, 68 to 74%) at 3 to 4 months
• 67% (95% CI, 63 to 71%) at 5 months or longer.

Effectiveness against ICU admission or high care was:

• 70% at 1 to 2 months
• 73% at 3 to 4 months
• 71% (95% CI, 65 to 76%) at 5 months or longer

Conclusion

Authors conclude: "After two doses, both vaccines were equally effective against severe disease caused by the Omicron variant. It is important to point out that these estimates of vaccine effectiveness were calculated in a South African population with a high background prevalence of SARS-CoV-2 exposure during the COVID-19 pandemic."

Collie adds, "My colleague Jared Champion (Senior Actuary, Discovery Health) and I are delighted to have collaborated with the leading scientists who have taken part in this important research, and we congratulate the team at large for completing and sharing this important piece of work."

• Read the SAMRC press release on these new findings: "The Sisonke study shows real world vaccine effectiveness against Omicron"

Interested in knowing more or reporting on these findings?

Please email MEDIA_RELATIONS_TEAM@discovery.co.za to request any updated data available since publication and to obtain any further context required.

Did you find this post interesting?

You may also be interested in reading our related post: The Lancet published an at-scale, real-world study on the excellent effectiveness of the single-dose Johnson & Johnson COVID-19 vaccine against serious illness during both South Africa's second and third waves of infection. Discovery Health provided an integral control group data set to this study.

Disclaimer