Structured PREreview of Relevance of Seasonal Revaccination against Respiratory Syncytial Virus in Hematology Patients: First Insights in Stem Cell Transplant Recipients

Does the introduction explain the objective of the research presented in the preprint?

Yes

The authors clearly explain the research objectives and provide relevant background on the vaccination against RSV among HSCT patients. The authors then discuss two important questions that the duration of vaccine protection remains poorly documented in seroresponders, and the probability of revaccination to improve immunogenicity in non-seroresponding patients remains unclear. To address the problems, the authors followed antibody responses over 12 months in 71 HSCT recipients and explored the potential benefits of revaccination before the next RSV season.

Are the methods well-suited for this research?

Somewhat appropriate

I think the methods are generally well-suited to the research objectives. The longitudinal observational design allows the authors to track antibody responses over 12 months, and I especially appreciated the use of ELISA to directly measure anti-RSVpreF IgG levels. Although the sample size of 71 patients is relatively small, I think it is reasonable given the specific immunocompromised population being studied. However, I have a few questions about the methodology. First, why was 18 months chosen as the cutoff between early and late vaccination? Second, only 22 of the original 71 patients received revaccination, and it is unclear how these patients were selected. This could introduce selection bias and affect the generalizability of the findings. Additionally, Table 1 shows substantial differences in immunosuppressive treatment and lymphocyte counts between the two groups, which could influence antibody responses independently of vaccination timing. I also wonder whether the Mann-Whitney test adequately accounts for repeated measurements from the same patients. Overall, I think the methods provide a good foundation for this preliminary study, but further clarification of patient selection and statistical analysis would strengthen the findings.

Are the conclusions supported by the data?

Somewhat supported

We think the conclusions are generally supported by the data, especially the finding that revaccination improves antibody responses in HSCT recipients who were vaccinated early after transplantation. The early-vaccinated group initially had a much lower seroconversion rate (14% vs. 63%), but showed a 23-fold increase in antibody levels after revaccination, compared with a 4-fold increase in the late-vaccinated group. Both groups also achieved comparable antibody titers after revaccination. However, the authors should more clearly distinguish between improved antibody responses and actual clinical protection; higher antibody levels do not necessarily translate into better protection against RSV infection. Overall, the findings are promising, but further evidence is needed before recommending a systematic annual revaccination strategy.

Are the data presentations, including visualizations, well-suited to represent the data?

Somewhat appropriate and clear

The figures and tables are generally clear and appropriate for presenting the results. Figure 1 effectively illustrates changes in antibody responses over time and after revaccination. One concern is the substantial decrease in sample size from 71 initially vaccinated patients to only 22 who received revaccination. A brief explanation of patient selection, perhaps through a patient flow diagram, would help readers better interpret the results.

How clearly do the authors discuss, explain, and interpret their findings and potential next steps for the research?

Somewhat clearly

The authors do a good job of interpreting their findings, particularly by connecting the stronger antibody responses after revaccination to the gradual recovery of immune function following HSCT. Their discussion of future research in other immunocompromised populations is relevant from both scientific and public health policy perspectives, and, of course, provides another clear direction for further studies. One suggestion would be to discuss more specifically how future studies could determine whether improved antibody responses actually translate into better clinical protection. Overall, the discussion is clear and insightful.

Is the preprint likely to advance academic knowledge?

Somewhat likely

This preprint makes a meaningful contribution to our understanding of RSV vaccination in HSCT recipients, especially since the benefits of seasonal revaccination remain so poorly understood in immunocompromised populations. One particularly important finding is that patients who responded poorly to vaccination initially showed substantially improved antibody responses after revaccination, suggesting that vaccination schedules may need to account for immune recovery following transplantation. Although the lack of direct evidence of clinical protection limit the broader implications, we think the study provides valuable evidence and raises important questions for future research. Overall, it is a promising contribution to help inform more individualized vaccination strategies.

Would it benefit from language editing?

No

The preprint is generally well-written, with clear scientific language and a logical flow between sections. Although there are a few minor grammatical issues and awkward expressions like “before the 2024-2025vaccination” and “Their immediate immunogenicity ... have been reported”, they do not affect readability or understanding. Some sentences could be refined for clarity, but I do not think extensive language editing is necessary.

Would you recommend this preprint to others?

Yes, but it needs to be improved

We would recommend this preprint to others, particularly researchers and clinicians interested in transplantation and vaccination strategies for immunocompromised patients. The study addresses an important and under-explored question, and its findings on improved antibody responses after revaccination are valuable. Some methodological limitations, like selection bias and the lack of direct evidence of clinical protection, should be addressed or more thoroughly discussed. Overall, I think this is a meaningful contribution to the field, and it could help inform vaccination strategies for HSCT recipients.

Is it ready for attention from an editor, publisher or broader audience?

Yes, after minor changes

This preprint is ready for editorial attention after some minor revisions. The research question is important, the methods are generally appropriate, and the findings provide valuable preliminary evidence on RSV revaccination in HSCT recipients. However, we would recommend clarifying how the 22 patients were selected for revaccination, more carefully distinguishing antibody responses from actual clinical protection, and correcting a few minor grammatical errors. These limitations do not undermine the overall value of the study, but addressing them would strengthen its scientific rigor and clarity before publication.

Competing interests

The authors declare that they have no competing interests.

Use of Artificial Intelligence (AI)

The authors declare that they did not use generative AI to come up with new ideas for their review.