Negative VE and rVE against severe COVID-19 outcomes

Several studies reported that COVID-19 vaccine effectiveness (VE) and relative vaccine effectiveness (rVE) against severe COVID-19 outcomes can turn negative after a few months.  

One recently published paper (data analyzed were from 8 December 2020 to 30 June 2021) concludes that For Doses 1 and 2 of ChAdOx1 and Dose 1 of BNT162b2, VE/rVE reached zero by approximately Days 60–80 and then went negative. By Day 70, VE/rVE was –25% (95% CI: –80 to 14) and 10% (95% CI: –32 to 39) for Doses 1 and 2 of ChAdOx1 (see Figure). The same trend was observed for BNT162b2 although it seemed to provide a better protection.

Another not-yet published paper found that vaccine effectiveness was waning for all studied doses, including the 4th booster that worked for 90 days. Among health-care workers who had not had previous SARS-CoV-2 infection, time-specific vaccine effectiveness decreased from 52% (95% CI, 45 to 58) during the first 5 weeks after vaccination to −2% (95% CI, −27 to 17) at 15 to 26 weeks.

Vaccine effectiveness for children was negligible or negative 3 months or more after vaccination (−1.7%; 95% CI, −16.9 to 11.5 among those who had completed their primary series between February 1, 2021, and June 30, 2021, according to this Qatar study)

According to a study from Netherlands, during the Omicron-period, vaccine effectiveness against infection (VE-infection) was -36% (95% CI: -88%-1%) for primary series and -30% (95% CI: -80%-6%) for booster vaccination. It was positive for infectiousness though - indicating that vaccinated people may be less likely to pass the virus to each other.  

Previously we discussed the Walgreens testing data that suggested waning and negative efficiency. Another previous post addressed reports from US and UK with the same conclusion. The latter study observed negative vaccine effectiveness (VE) for the third dose since December 20, 2021, with a significantly increased proportion of SARS-CoV2 cases hospitalizations, and deaths among the vaccinated; and a decreased proportion of cases, hospitalizations, and deaths among the unvaccinated. UK data included SARS-CoV2 cases reported under pillar 1 (public health laboratories and hospitals) and pillar 2 (community testing) among various age groups (0-19, 20-29, 30-49, 50-69, ≥50, ≥70 and ≥80 years of age) from September 28, 2020, to May 1, 2022.


Steven Kerr, Stuart Bedston, Declan T Bradley, Mark Joy, Emily Lowthian, Rachel M Mulholland, Ashley Akbari, F D Richard Hobbs, Srinivasa Vittal Katikireddi, Simon de Lusignan, Igor Rudan, Fatemeh Torabi, Ruby S M Tsang, Ronan A Lyons, Chris Robertson, Aziz Sheikh, Waning of first- and second-dose ChAdOx1 and BNT162b2 COVID-19 vaccinations: a pooled target trial study of 12.9 million individuals in England, Northern Ireland, Scotland and Wales, International Journal of Epidemiology, 2022;, dyac199,

Effectiveness of mRNA-1273 against infection and COVID-19 hospitalization with SARS-CoV-2 Omicron subvariants: BA.1, BA.2, BA.2.12.1, BA.4, and BA.5 Hung Fu Tseng, Bradley K. Ackerson, Katia J. Bruxvoort, Lina S. Sy, Julia E. Tubert, Gina S. Lee, Jennifer H. Ku, Ana Florea, Yi Luo, Sijia Qiu, Soon Kyu Choi, Harpreet S. Takhar, Michael Aragones, Yamuna D. Paila, Scott Chavers, Lei Qian medRxiv 2022.09.30.22280573; doi:

Chemaitelly H, AlMukdad S, Ayoub HH, Altarawneh HN, Coyle P, Tang P, Yassine HM, Al-Khatib HA, Smatti MK, Hasan MR, Al-Kanaani Z, Al-Kuwari E, Jeremijenko A, Kaleeckal AH, Latif AN, Shaik RM, Abdul-Rahim HF, Nasrallah GK, Al-Kuwari MG, Al-Romaihi HE, Butt AA, Al-Thani MH, Al-Khal A, Bertollini R, Abu-Raddad LJ. Covid-19 Vaccine Protection among Children and Adolescents in Qatar. N Engl J Med. 2022 Nov 2. doi: 10.1056/NEJMoa2210058. Epub ahead of print. PMID: 36322837.

Canetti M, Barda N, Gilboa M, Indenbaum V, Asraf K, Gonen T, Weiss-Ottolenghi Y, Amit S, Doolman R, Mendelson E, Freedman LS, Kreiss Y, Lustig Y, Regev-Yochay G. Six-Month Follow-up after a Fourth BNT162b2 Vaccine Dose. N Engl J Med. 2022 Nov 9. doi: 10.1056/NEJMc2211283. Epub ahead of print. PMID: 36351266.


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