Recruitment into antibody prevalence studies: a randomized trial of postcards vs. letters as invitations.
BMC Med Res Methodol
; 23(1): 170, 2023 07 22.
Article
em En
| MEDLINE
| ID: mdl-37481522
ABSTRACT
BACKGROUND:
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.METHODS:
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.RESULTS:
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% CI1.4-2.5]).CONCLUSION:
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.Palavras-chave
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
RNA Viral
/
COVID-19
Tipo de estudo:
Clinical_trials
/
Observational_studies
/
Prevalence_studies
/
Risk_factors_studies
Limite:
Humans
Idioma:
En
Revista:
BMC Med Res Methodol
Assunto da revista:
MEDICINA
Ano de publicação:
2023
Tipo de documento:
Article
País de afiliação:
Estados Unidos