Immune escape and waning immunity of COVID-19 monovalent mRNA vaccines against symptomatic infection with BA.1/BA.2 and BA.5 in Japan

Takeshi Arashiro, Yuzo Arima, Jin Kuramochi, Hirokazu Muraoka, Akihiro Sato, Kumi Chubachi, Kunihiro Oba, Atsushi Yanai, Hiroko Arioka, Yuki Uehara, Genei Ihara, Yasuyuki Kato, Naoki Yanagisawa, Yoshito Nagura, Hideki Yanai, Akihiro Ueda, Akira Numata, Hideaki Kato, Hideaki Oka, Yusuke NishidaKoji Ishii, Takao Ooki, Yuki Nidaira, Takahiro Asami, Torahiko Jinta, Akira Nakamura, Daisuke Taniyama, Kei Yamamoto, Katsushi Tanaka, Kankuro Ueshima, Tetsuji Fuwa, Ashley Stucky, Tadaki Suzuki, Chris Smith, Martin Hibberd, Koya Ariyoshi, Motoi Suzuki

Research output: Contribution to journalArticlepeer-review

3 Citations (Scopus)

Abstract

Background: Repeated emergence of variants with immune escape capacity and waning immunity from vaccination are major concerns for COVID-19. We examined whether the surge in Omicron subvariant BA.5 cases was due to immune escape or waning immunity through vaccine effectiveness (VE) evaluation. Methods: A test-negative case-control study was conducted in 16 clinics/hospitals during the BA.1/BA.2-dominant and BA.5-dominant periods. VE against symptomatic infection was estimated after adjusting for age, sex, comorbidity, occupation, testing frequency, prior infection, close contact history, clinic/hospital, week, and preventive measures. Absolute VE (aVE) was calculated for 2/3/4 doses, compared to the unvaccinated. Relative VE (rVE) was calculated, comparing 3 vs 2 and 4 vs 3 doses. Results: 13,025 individuals were tested during the BA.1/BA.2-dominant and BA.5-dominant periods with similar baseline characteristics. For BA.1/BA.2, aVE was 52 % (95 %CI:34–66) 14 days-3 months post-dose 2, 42 % (29–52) > 6 months post-dose 2, 71 % (64–77) 14 days-3 months post-dose 3, and 68 % (52–79) 3–6 months post-dose 3. rVE was 49 % (38–57) 14 days-3 months post-dose 3 and 45 % (18–63) 3–6 months post-dose 3. For BA.5, aVE was 56 % (27–73) 3–6 months post-dose 2, 32 % (12–47) > 6 months post-dose 2, 70 % (61–78) 14 days-3 months post-dose 3, 59 % (48–68) 3–6 months post-dose 3, 50 % (29–64) > 6 months post-dose 3, and 74 % (61–83) ≥ 14 days post-dose 4. rVE was 56 % (45–65) 14 days-3 months post-dose 3, 39 % (27–48) 3–6 months post-dose 3, 25 % (-2–45) > 6 months post-dose 3, and 30 % (-6–54) ≥ 14 days post-dose 4. Conclusions: Booster doses initially provided high protection against BA.5 at a level similar to that against BA.1/BA.2. However, the protection seemed shorter-lasting against BA.5, which likely contributed to the surge. Furthermore, rVE post-dose 4 was low even among recent vaccinees. These results support the introduction of variant-containing vaccines and emphasize the need for vaccines with longer duration of protection.

Original languageEnglish
Pages (from-to)6969-6979
Number of pages11
JournalVaccine
Volume41
Issue number47
DOIs
Publication statusPublished - 13-11-2023

All Science Journal Classification (ASJC) codes

  • Molecular Medicine
  • General Immunology and Microbiology
  • General Veterinary
  • Public Health, Environmental and Occupational Health
  • Infectious Diseases

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