Factors associated with vasovagal reactions in apheresis plasma and whole blood donors: a statistical-epidemiological study in a European donor cohort

Donor complication rates in whole blood, plasma and platelet donors: Age versus experience

BACKGROUND

Many blood banks use upper age limits for donors out of concern for a higher donor complication rate in older donors. Experienced donors are known to have lower donor complication rates, and older donors are often more experienced, confounding the effect of age on donor complication rate.

STUDY DESIGN AND METHODS

We studied donor complication rates in whole blood, plasma, and plateletpheresis donors from 2012 to 2022. Donor complication rates were compared between age groups in inexperienced (<20th donation) and experienced (≥20th donation) donors. In addition to this direct comparison, we made use of logistic regression with finer-grained experience groups, to further quantify the effects of age, experience and other factors on donor complication rate.

RESULTS

While overall rate of vasovagal reaction was lower, rate of moderate/severe vasovagal syncope was highest in 70-79 year donors, however, only reached significance for plasma donors. Furthermore, rates of failed stab were highest in this age group. Hematoma rate showed a U-shaped pattern with regard to age, where the rate was not higher in the 70-79 year age group than in the 18-23 year age group. Pain decreased with age, however, rates were higher in the 70-79 year age group than in the 65-69 year age group.

DISCUSSION

When properly accounting for donor experience, donor complication rate profiles clearly change with age. The increased risk for moderate/severe vasovagal syncope in older donors should be clearly communicated. Extra caution is needed if these donors are accepted for first-time donations.

Development and validation of a nomogram for predicting the risk of vasovagal reactions after plasma donation

BACKGROUND AND OBJECTIVES

Vasovagal reactions (VVRs) are the most common adverse reactions and are frequently associated with serious donor adverse events. Even mild VVRs can lead to a significant reduction in the likelihood of subsequent donations. The purpose of this study is to explore the factors related to the occurrence of VVRs after plasma donation and to construct a nomogram to identify individuals at risk for VVRs to improve the safety of plasma donors.

MATERIALS AND METHODS

We collected the donation data from July 2019 to June 2020 from a plasma center in Sichuan, China, to explore the independent risk factors for vasovagal reactions. From these data, we constructed and validated a predictive model for vasovagal reactions.

RESULTS

VVRs after plasma donation occurred 737 times in 120 448 plasma donations (0.66%). Gender, season, donor status, weight, pulse, duration of donation, and cycle were independent risk factors for VVRs (P< 0.05). The concordance index (C-index) of a logistic model in the derivation cohort was 0.916, with a Hosmer-Lemeshow goodness-of-fit probability of 0.795. The C-index of a logistic model in the validation cohort was 0.916, with a Hosmer-Lemeshow goodness-of-fit probability of 0.224. The calibration curve showed that the predicted results were in good agreement with the actual observed results.

CONCLUSION

This study preliminarily constructed and verified a prediction model for VVRs after plasma donation. The model nomogram is practical and can identify high-risk donors.

Novel risk patterns of vasovagal reactions in NZ blood donations complicated by COVID-19 restrictions

Introduction

Vasovagal reactions (VVRs) are common but complex donor adverse reactions (DAEs) in blood donations. VVRs have been extensively studied with a multitude of risk factors identified including young age, female gender and first-time donor status. How they may interplay remains obscure.

Methods

A total of 1,984,116 blood donations and 27,952 immediate VVRs (iVVRs) and 1,365 delayed VVRs (dVVRs) reported between 2011 and 2021 in NZ were used in multivariate logistic regression analyses each concerning donations with iVVRs as cases and those free of DAEs as controls. For each analysis stepwise selection was used to identify the best model and risk factors carrying significant main effects and/or interactions. Identified interactions informed further in-depth regression analyses to dissect iVVR risk patterns.

Results

Over 95% of VVRs were iVVRs that had lower female preponderance and deferrals than dVVRs. iVVRs had a school seasonal pattern in whole blood donations driven by first-time donors from schools/colleges, and interactions between gender and age group differentiating the first-time from repeat donations. Subsequent regression analyses identified the known and novel risk factors of year and mobile collection sites and their interactions. iVVR rates were roundly elevated in 2020 and 2021 probably because of COVID-19 restrictions like facemask wearing. Exclusion of the 2020 and 2021 data removed the interactions with year, but confirmed interactions of gender with mobile collection sites (p = 6.2e-07) in first-time donations only and with age group in repeat donations only (p < 2.2e-16), together indicating young female donors at the highest risk of iVVRs. Our results also revealed that donation policy changes contributed to the year effects; donors had a lower iVVR risk at mobile sites than well-medicalized donation centers probably because of under-reporting.

Conclusion

Modeling statistical interactions is valuable in identifying odds and revealing novel iVVR risk patterns and insights into blood donations.

Reports of acute adverse events in mRNA COVID-19 vaccine recipients after the first and second doses in Japan

Mass vaccination against coronavirus disease 2019 (COVID-19) is ongoing in many countries worldwide. This study reports the occurrence of acute adverse events among vaccine recipients at a mass vaccination center in Japan. Between August and November 2021, approximately 130,000 individuals received two mRNA vaccine doses (mRNA-1273; Moderna) at the vaccination center. Acute adverse events at the site were observed in 1.1% of the recipients after the first dose and in 0.4% of the recipients after the second dose. The most common event was vasovagal syncope/presyncope, followed by acute allergic reactions. The occurrence rate of vasovagal syncope/presyncope was highest in the young population of those aged 16–29 years, but such age-dependency was not apparent in acute allergic reactions. Both symptoms were more prevalent in women than in men. Vasovagal syncope/presyncope occurred mainly within 20 min of the injection, whereas nearly half of the episodes of acute allergic reactions occurred after 20 min. The vaccine being injected while the recipient was in the supine position effectively reduced the occurrence of vasovagal syncope/presyncope. In summary, the suggested risk factors for vasovagal syncope/presyncope included a young age and female sex. The vaccine being injected while the recipient was in the supine position would reduce the risk of vasovagal syncope/presyncope.

Vasovagal reactions in whole blood and apheresis donors: a cross-sectional study on donor haemovigilance data from 2016 to 2019 in Italy

BACKGROUND

Acute and delayed vasovagal reactions (VVR) are the most frequent adverse reactions (AR) associated with donations. The aim of this study was to provide the data of the Italian donor haemovigilance system and contextualise the VVR data within the international framework, as well as evaluating, among first-time donors, the association of gender and age and the prevalence of VVR compared to other AR.

MATERIALS AND METHODS

The prevalence analysis was performed on VVR and other AR notified to the Italian haemovigilance system from 2016 to 2019. The analysis on the association of gender and age group and VVR prevalence was performed on first-time donations. The definitions and severity of AR were as set out in the 2014 ISBT/IHN international standards.

RESULTS

From 2016 to 2019, 34,519 AR were notified, of which 87.1% were VVR. The overall VVR prevalence was 25.0/10,000 donations and the overall prevalence of other AR was 3.7/10,000 donations. All the estimated prevalences of AR were higher for first-time donations than for regular donations and lower for whole blood than for apheresis donations. No difference was noted between whole blood and apheresis donations for VVR with complications or injuries. The prevalence of AR among first-time donors was higher in females than in males. The prevalence of VVR decreased as donor age increased.

DISCUSSION

The prevalence of VVR related to blood donation was very low and similar to those calculated by other haemovigilance systems. Among first-time donors, the prevalence of AR was higher in females than in males. The higher prevalence of VVR in young donors and a significant decreasing trend by age group confirmed the results reported in the literature. Finally, no trend by age group in first-time donors was observed for other AR to donations.

Plasmavigilance-Adverse events among US Source plasma donors

Background

Source plasma (SP) is the primary starting material for 87% of plasma‐derived medicinal products globally. Plasmavigilance is a program designed to collect, analyze, and monitor donor adverse events (AEs) across the SP collection industry. Donor retention depends on donors having a safe and satisfactory experience. This study analyzes AE rates and SP donor characteristics that may be predictors of an AE.

Study Design and Methods

Donation data for 1.1 million donors making 12,183,182 SP donations over a 4‐month period were analyzed. This represented approximately 72% of the donations collected by the U.S. plasma industry. The Standard for Recording Donor Adverse Events was used for AE definitions and classifications.

Results

The overall AE rate was 15.85/10⁴ donations. The two AEs with the highest rates were Hypotensive and Phlebotomy events (8.32 and 5.91/10⁴ donations, respectively). Females had higher overall AE rates than males (25.76 vs. 9.85/10⁴ donations), and first‐time donors had higher overall AE rates than repeat donors (136.66 vs. 12.37/10⁴ donations). Weight, body mass index, age, and pre‐donation estimated blood volume also were predictors of AE.

Discussion

SP donors have low AE rates with 90% being events classified as Hypotensive or Phlebotomy. Special attention and mitigation strategies should be directed to donors who are young, lightweight (between 100 and 124 pounds), female, or first‐time donors to further reduce the incidence of AE, continue to ensure the donor has a safe experience, and facilitate donor retention.

See editorial on page 2803–2805, in this issue

Vasovagal reaction among whole blood donors in Hospital Pulau Pinang. A statistical-epidemiological study

CONTEXT

Whole blood donation is generally considered a safe procedure; however, a small percentage of donors could develop vasovagal reactions (VVRs) during or after completion of blood donation.

AIMS

This study was undertaken to establish the prevalence of VVR among whole blood donors in Hospital Pulau Pinang and to investigate factors that lead to its occurrence.

SETTINGS AND DESIGN

A cross-sectional study was conducted involving 27,890 whole blood donations in 2016.

SUBJECTS AND METHODS

For each donation, donor's demographic and blood donation-related information was extracted from the blood bank database.

STATISTICAL ANALYSIS USED

Qualitative data including age group, sex, race, frequency, and location of donation were analyzed using Chi-square tests, while blood pressure was analyzed using t-test.

RESULTS

Overall, 425 cases of VVRs were reported, resulting in a VVR rate of 1.5% (one event in every 65 donations). We found a statistically significant association (P < 0.05) between the occurrence of VVRs with the young age group, female gender, Indian race, first-time donor, lower predonation blood pressure, and donation performed in a mobile donation campaign. The most common vasovagal symptoms are lightheadedness (88%), followed by nausea (5.4%), muscle twitching (3.5%), vomiting (1.4%), loss of consciousness <30 s (1.4%), and paresthesia (0.2%).

CONCLUSIONS

The prevalence of VVRs among whole blood donors in Hospital Pulau Pinang appeared to be low. Our study reaffirms that blood donation is a relatively safe process, and the incidence of VVR can be further reduced by ensuring strict screening procedure before blood donation.

Incidence of adverse reaction in blood donation: a systematic review

There are a lot of reports related to adverse reactions post blood donation. The present study is designed to investigate the incidence of adverse reactions in blood donation around the world. This research was conducted through searching databases such as PubMed, Web of Science, Scopus, EmBase, Ovid, as well as the specialized journal of TRANSFUSION without any time limit by using the keywords including "Adverse Event", "Adverse Effect", "Adverse Reaction", "Complication", "Side Effect", "Vasovagal Reaction", "Local Reaction", "General Reaction", "Allergic Reaction", "Blood Donor", and "Blood Donation". In the initial search, 7054 documents were found, of which 2517 duplicates were excluded. After screening the remaining 4,537 documents, 97 one were reviewed for quality assessment, of which 30 with the appropriate quality were selected for the review process. The results of the study showed that the reactions caused by blood donation are very different. Most reactions were systemic, and ranged from 0.08 to 13 percent in different countries. The incidence of adverse reactions in blood donation differ across the countries which might be related to the donors' characteristics. The difference did even existed in studies conducted in the same country and the same year. This suggests that many factors can cause adverse reactions in blood donation, and that a wide range of them investigated in one study, most of which were systemic.