Intended for healthcare professionals

  1. Research
  2. Effectiveness of mRNA...
  3. Effectiveness of mRNA vaccines and waning of protection against SARS-CoV-2 infection and severe covid-19 during predominant circulation of the delta variant in Italy: retrospective cohort study
CCBYNC Open access
Research

Effectiveness of mRNA vaccines and waning of protection against SARS-CoV-2 infection and severe covid-19 during predominant circulation of the delta variant in Italy: retrospective cohort study

BMJ 2022; 376 doi: https://doi.org/10.1136/bmj-2021-069052 (Published 10 February 2022) Cite this as: BMJ 2022;376:e069052

Read our latest coverage of the coronavirus pandemic

All rapid responses

Rapid responses are electronic comments to the editor. They enable our users to debate issues raised in articles published on bmj.com. A rapid response is first posted online. If you need the URL (web address) of an individual response, simply click on the response headline and copy the URL from the browser window. A proportion of responses will, after editing, be published online and in the print journal as letters, which are indexed in PubMed. Rapid responses are not indexed in PubMed and they are not journal articles. The BMJ reserves the right to remove responses which are being wilfully misrepresented as published articles or when it is brought to our attention that a response spreads misinformation.

From March 2022, the word limit for rapid responses will be 600 words not including references and author details. We will no longer post responses that exceed this limit.

The word limit for letters selected from posted responses remains 300 words.

Re: Effectiveness of mRNA vaccines and waning of protection against SARS-CoV-2 infection and severe covid-19 during predominant circulation of the delta variant in Italy: retrospective cohort study

Dear Editor

This article highlights the importance of Covid-19 booster vaccinations, and the potential need to shorten the window between vaccinations to improve immunity against SARS-COV-2. With this, we need to consider resources, as biannual intramuscular vaccinations administered by health professionals is a costly requirement.

Going forwards, intranasal vaccines may reduce reliance on services to provide booster vaccines, as these can be self-administered in a non-healthcare setting [1]. They have also shown potential to reduce viral shedding, and therefore reduce transmission, by mucosal immune response in the upper and lower respiratory tracts [2,3].

Of course, it will be crucial to adopt a targeted approach in identifying high risk groups for more frequent Covid-19 vaccine boosters. This group logically includes the elderly, immunocompromised, and health workers. However, this should also include shift workers from non-healthcare backgrounds, as it has been shown that shift work is associated with more severe Covid-19 disease, requiring hospital admission [4,5].

Overall, a practical approach to frequent Covid-19 booster vaccinations needs to be considered, and this may be through the use of intranasal vaccination in targeted populations.

References
1. Chavda V, Vora L, Pandya A, Patravale V. Intranasal vaccines for SARS-CoV-2: From challenges to potential in COVID-19 management. Drug Discovery Today. 2021;26(11):2619-2636.
2. Mao T, Israelow B, Suberi A, Zhou L, Reschke M, Peña-Hernández M et al. Unadjuvanted intranasal spike vaccine booster elicits robust protective mucosal immunity against sarbecoviruses. 2022;.
3. Hassan A, Kafai N, Dmitriev I, Fox J, Smith B, Harvey I et al. A Single-Dose Intranasal ChAd Vaccine Protects Upper and Lower Respiratory Tracts against SARS-CoV-2. Cell. 2020;183(1):169-184.e13.
4. Maidstone R, Anderson S, Ray D, Rutter M, Durrington H, Blaikley J. Shift work is associated with positive COVID-19 status in hospitalised patients. Thorax. 2021;76(6):601-606.
5. Rowlands A, Gillies C, Chudasama Y, Davies M, Islam N, Kloecker D et al. Association of working shifts, inside and outside of healthcare, with severe COVID−19: an observational study. BMC Public Health. 2021;21(1).

Competing interests: No competing interests

13 February 2022
Saskia Locke
Doctor
Wishaw General Hospital, Lanarkshire, Scotland

Japan needs to accelerate the third dose

Dear Editor

The results demonstrated by Fabiani et al. (1) suggest that high-risk people aged ≥60 years should receive a booster dose of vaccine for COVID-19 six months after the primary vaccination cycle.

Only 7.9% of the eligible population in Japan received the third dose of the vaccine (2), compared to 65.5% in the UK (3). There are several reasons for the significant vaccination delay in Japan. First, the government did not take measures to faster the third dose implementation: It planned eight months after the second dose. The backdrop of the failure to act was a marked reduction of Japanese COVID-19 cases in December 2021. The government could have accelerated the third dose plan in response to the outbreak of the Omicron strain worldwide. Second, there might be vaccine hesitancy in Japan as the domestic media sensationalised a relatively high occurrence of its side effects, such as fever, malaise and the Moderna arm. Thus, Japanese people prefer Pfizer's vaccine to Moderna's one, resulting in a lack of appointments for Pfizer's vaccine and not progressing Moderna's vaccine.

The Japanese government should appropriately and scientifically inform the necessity of the third dose six months after the second dose and accelerate the third dose.

References
1. Fabiani M, Puopolo M, Morciano C, Spuri M, Spila Alegiani S , Filia A et al. Effectiveness of mRNA vaccines and waning of protection against SARS-CoV-2 infection and severe covid-19 during predominant circulation of the delta variant in Italy: retrospective cohort study BMJ 2022; 376 :e069052 doi:10.1136/bmj-2021-069052
2. Nihon Keizai Shinbun. Japan's vaccination situation in a chart: Corona vaccine. 2022. https://vdata.nikkei.com/newsgraphics/coronavirus-japan-vaccine-status/ (Accessed 11 February 2022)
3. GOV.UK Coronavirus (COVID-19) in the UK. 2022. https://coronavirus.data.gov.uk/details/vaccinations (Accessed 11 February 2022)

Competing interests: No competing interests

11 February 2022
Koki Kato
GP
Madoka Family Clinic; Academic & Research Centre, Hokkaido Centre for Family Medicine
1‐40, Asumi, Ogori, Fukuoka 8380109, Japan.
Back to top