Division of Infectious Diseases and Geographic Medicine, Department of Medicine, Stanford University, 300 Pasteur Drive, Stanford, CA, 94305, USA.
Division of Nuclear Medicine and Molecular Imaging, Department of Radiology, Stanford University, Stanford, USA.
BMC Med Res Methodol. 2023 Jul 22;23(1):170. doi: 10.1186/s12874-023-01992-8.
In a potential epidemic of an emerging infection, representative population-based serologic studies are required to determine the extent of immunity to the infectious agent, either from natural infection or vaccination. Recruitment strategies need to optimize response rates.
Within a seroepidemiologic study to determine the true burden of SARS-CoV2 infection in two Bay Area counties, we evaluated whether letter (L) or postcard (P) invitations with reminders were more effective at recruiting participant households. Using geographic, probability-based sampling, 9,999 representative addresses, split between Santa Clara and Solano counties, were randomized to receive an initial invitation (L or P); a randomized reminder mailing sent two weeks later to all non-respondents created four mailing type groups (L/L, L/P, P/L, P/P). Interested households provided contact information via survey to perform blood spot collection at home for testing and then receive SARS-CoV2 serology results. Comparison of demographics among respondents and non-respondents used census tract data.
Receiving any reminder mailing increased household response rates from 4.2% to between 8-13% depending on mailing combination. Response rates from two letters were 71% higher than from two postcards (13.2% vs. 7.7%, OR = 1.83 [95% CI: 1.5-2.2]). Respondents were older, more educated and more likely white than non-respondents. Compared to Solano county, Santa Clara county had different demographics and increased household response rates (L/L: 15.7% vs 10.7%; P/P: 9.2% vs. 6.1%; p < 0.0001); the effect of mailing types, however, was the same (L/L vs. P/P: Santa Clara: OR = 1.83 [95% CI: 1.4-2.3]; Solano: OR = 1.84 [95% CI:1.4-2.5]).
Letters, as both invitations and reminders, are a more effective recruitment tool than postcards and should be considered when seeking a representative population-based sample for serological testing.
在新兴传染病的潜在流行中，需要进行基于代表性人群的血清学研究，以确定对传染性病原体的免疫程度，无论是来自自然感染还是疫苗接种。招募策略需要优化响应率。
在一项旨在确定两个湾区县 SARS-CoV2 感染真实负担的血清流行病学研究中，我们评估了信件（L）或明信片（P）邀请加提醒是否更有效地招募参与者家庭。使用地理、概率抽样，将 9999 个代表性地址在圣克拉拉县和索拉诺县之间随机分配，以接收初始邀请（L 或 P）；两周后向所有未回复者发送随机提醒邮件，创建了四种邮件类型组（L/L、L/P、P/L、P/P）。有兴趣的家庭通过调查提供联系信息，在家中进行血液斑采集进行检测，然后接收 SARS-CoV2 血清学结果。使用人口普查区数据比较回复者和未回复者的人口统计学特征。
收到任何提醒邮件都会使家庭的回复率从 4.2%提高到 8-13%，具体取决于邮件组合。两封信件的回复率比两张明信片高 71%（13.2%比 7.7%，OR=1.83[95%CI：1.5-2.2]）。回复者比未回复者年龄更大、受教育程度更高、更有可能是白人。与索拉诺县相比，圣克拉拉县的人口统计学特征不同，家庭回复率也更高（L/L：15.7%比 10.7%；P/P：9.2%比 6.1%；p<0.0001）；然而，邮件类型的效果是相同的（L/L 比 P/P：圣克拉拉：OR=1.83[95%CI：1.4-2.3]；索拉诺：OR=1.84[95%CI：1.4-2.5]）。
信件，无论是邀请还是提醒，都是比明信片更有效的招募工具，在为血清学检测寻求代表性人群样本时应予以考虑。
Zotero 插件