Characterizing U.S. mothers with high human papillomavirus vaccine intent yet unvaccinated adolescents.

HPV vaccination rates remain suboptimal in the United States. While the current literature focuses on expressly hesitant parents, few studies have examined parents with "high intent", or those indicating they definitely will vaccinate and have had the opportunity but not yet vaccinated their adolescents. Our objective was to differentiate characteristics of mothers with high intent from those who already vaccinated their adolescents using various socioeconomic, previous vaccine decision-making, and healthcare provider relationship-related variables. English-speaking mothers or female guardians of adolescents ages 11-14 years living in low HPV vaccine uptake states within the U.S. in September 2018 were recruited from a national survey panel as part of a larger study. We assessed HPV vaccine status of their adolescents and categorized respondents into two categories: Already Vaccinated and High Intent. We assessed differences using a multivariable logistic regression model. Among 2406 mothers, 18% reported high intent vs. 82% already having vaccinated. Mothers with high intent were more likely to identify as non-Hispanic White (p = 0.01), to have a younger adolescent (p < 0.001), and to report not receiving a provider HPV vaccination recommendation (p < 0.001). Mothers who estimated that half/more (vs. less) of their child's friends have received/will receive the vaccine had higher odds of already vaccinating (p < 0.001). Our findings suggest that clinicians may be able to improve HPV vaccination uptake within their practices by giving repeated, high-quality recommendations to parents of children who are not yet vaccinated. Additionally, these findings indicate perceived social norms may play a large role in on-time vaccine uptake. Reassuring hesitant parents that most parents accept the vaccine may also improve uptake in clinical practice.

Trusted messengers and trusted messages: The role for community-based organizations in promoting COVID-19 and routine immunizations.

We sought to explore the trust and influence community-based organizations have within the communities they serve to inform public health strategies in tailoring vaccine and other health messages. A qualitative study was conducted between March 15 - April 12, 2021 of key informants in community-based organizations serving communities in and around Philadelphia, Pennsylvania. These organizations serve communities with high Social Vulnerability Index scores. We explored four key questions including: (1) What was and continues to be the impact of COVID-19 on communities; (2) How have trust and influence been cultivated in the community; (3) Who are trusted sources of information and health messengers; and (4) What are the community's perceptions about vaccines, vaccinations, and intent to vaccinate in the context of the COVID-19 pandemic. Fifteen key informants from nine community-based organizations who serve vulnerable populations (e.g., mental health, homeless, substance use, medically complex, food insecurity) were interviewed. Five key findings include: (1) The pandemic has exacerbated disparities in existing social determinants of health for individuals and families and have created new concerns for these communities; (2) components of how to build the trust and influence (e.g., demonstrate empathy, create a safe space, deliver on results)resonated with key informants; (3) regardless of the source, presenting health information in a respectful and understandable manner is key to effective delivery; (4) trust and influence can be transferred by association to a secondary messenger connected to or introduced by the primary trusted source; and (5) increased awareness about vaccines and vaccinations offers opportunities to think differently, changing previously held beliefs or attitudes, as many individuals are now more cognizant of risks associated with vaccine-preventable diseases and the importance of vaccines. Community-based organizations offer unique opportunities to address population-level health disparities as trusted vaccine messengers to deliver public health messages.

Persuading the "Movable Middle": Characteristics of effective messages to promote routine and COVID-19 vaccinations for adults and children - The impact of COVID-19 on beliefs and attitudes.

PURPOSE: We sought to 1) explore trusted sources for vaccine information, 2) describe persuasive characteristics of trusted messages promoting routine and COVID-19 vaccines for children and adults and 3) explore how the pandemic has impacted attitudes and beliefs about routine vaccinations. We conducted a mixed method cross-sectional study between May 3-June 14, 2021 including a survey and six focus groups among a sub-set of survey respondents. A total of 1,553 survey respondents (from which n = 33 participated in the focus groups) including adults without children under age nineteen years (n = 582) and parents with children under age nineteen years (n = 971). RESULTS: Primary care providers, family, and credible sources, characterized as known and well-established entities, were top sources of vaccine information. Neutrality, honesty, and having a trusted source to rely on in sorting through volumes of sometimes conflicting information were highly valued. Trustworthy qualities about sources included: 1) expertise, 2) fact-based, 3) unbiased, and 4) having an established process for sharing information. Because of the evolving nature of the pandemic, attitudes and beliefs about COVID-19 vaccine and sources of COVID-19 information differed from typical views about routine vaccines. Of 1,327 (85.4 %) survey respondents, 12.7 % and 9.4 % of adults and parents cited that the pandemic impacted their attitudes and beliefs. Among these respondents, 8 % of adults and 3 % of parents cited more favorable attitudes and beliefs about getting vaccinated with routine vaccines because of the pandemic. CONCLUSION: Vaccine attitudes and beliefs which inform intent to vaccinate can change and differ among different vaccines. Messaging should be tailored to resonate with parents and adults to improve vaccine uptake.

Using a patient portal as a recruitment tool to diversify the pool of participants in COVID-19 vaccine clinical trials.

The coronavirus disease 2019 (COVID-19) pandemic has disproportionately affected racial/ethnic minorities in the United States, who are underrepresented in clinical trials. We assessed the feasibility of using the University of Pennsylvania Health System electronic health record patient portal to diversify the pool of participants in COVID-19 vaccine clinical trials. The patient portal was used to send invitations to eligible individuals living in zip codes with high rates of racial/ethnic minorities. The 5614 invited consisted of 96.7% black, 1.3% Hispanic/Latinx, and 1.5% white. The overall response rate was 5.4%, with lower response rates among Black (3.8%) and Hispanic/Latinx (9.6%) as compared to white individuals (91.6%). Among respondents, black individuals had lower rates of interest in participating (26.7%), as compared to white (65.8%) and Hispanic/Latinx (71.4%) individuals. Of 115 respondents who expressed interest, 9 enrolled in the clinical trial, which included 6 black, 3 white, and 1 Hispanic/Latinx. During phone outreach to nonresponders and decliners, common reasons for declining included mistrust of the COVID-19 vaccine, underlying health conditions, and logistical barriers to trial participation. Because of low rates of patient portal account activation and use, compounded with vaccine hesitancy, this method yielded a small number of interested individuals.

Comparing COVID-19 Vaccination Outcomes with Parental Values, Beliefs, Attitudes, and Hesitancy Status, 2021-2022.

Despite the availability of safe and effective COVID-19 vaccines, vaccine acceptance has been low, particularly among parents. More information is needed on parental decision-making. We conducted a prospective cohort study from October 2021 to March 2022 among 334 parents in a large urban/suburban pediatric primary care network and linked longitudinal survey responses about attitudes and beliefs on vaccination, social norms, and access to vaccination services for COVID-19 to electronic health-record-derived vaccination outcomes for their eldest age-eligible children in June 2022. The odds of accepting two doses of COVID-19 vaccine for their child was higher in respondents who indicated the COVID-19 vaccine would be very safe (aOR [CI]: 2.69 [1.47−4.99], p = 0.001), as well as those who previously vaccinated their child against influenza (aOR [CI]: 4.07 [2.08−8.12], p < 0.001). The odds of vaccinating their child were lower for respondents who attended suburban vs. urban practices (aOR [CI]: 0.38 [0.21−0.67], p = 0.001). Parents in the cohort were active users of social media; the majority (78%) used their phone to check social media platforms at least once per day. Our findings suggest that healthcare providers and policymakers can focus on improving vaccination coverage among children living in suburban neighborhoods through targeted mobile-based messaging emphasizing safety to their parents.

Design, Implementation, and Outcomes of a Volunteer-Staffed Case Investigation and Contact Tracing Initiative at an Urban Academic Medical Center.

Importance: The COVID-19 pandemic has claimed nearly 6 million lives globally as of February 2022. While pandemic control efforts, including contact tracing, have traditionally been the purview of state and local health departments, the COVID-19 pandemic outpaced health department capacity, necessitating actions by private health systems to investigate and control outbreaks, mitigate transmission, and support patients and communities. Objective: To investigate the process of designing and implementing a volunteer-staffed contact tracing program at a large academic health system from April 2020 to May 2021, including program structure, lessons learned through implementation, results of case investigation and contact tracing efforts, and reflections on how constrained resources may be best allocated in the current pandemic or future public health emergencies. Design, Setting, and Participants: This case series study was conducted among patients at the University of Pennsylvania Health System and in partnership with the Philadelphia Department of Public Health. Patients who tested positive for COVID-19 were contacted to counsel them regarding safe isolation practices, identify and support quarantine of their close contacts, and provide resources, such as food and medicine, needed during isolation or quarantine. Results: Of 5470 individuals who tested positive for COVID-19 and received calls from a volunteer, 2982 individuals (54.5%; median [range] age, 42 [18-97] years; 1628 [59.4%] women among 2741 cases with sex data) were interviewed; among 2683 cases with race data, there were 110 Asian individuals (3.9%), 1476 Black individuals (52.7%), and 817 White individuals (29.2%), and among 2667 cases with ethnicity data, there were 366 Hispanic individuals (13.1%) and 2301 individuals who were not Hispanic (82.6%). Most individuals lived in a household with 2 to 5 people (2125 of 2904 individuals with household data [71.6%]). Of 3222 unique contacts, 1780 close contacts (55.2%; median [range] age, 40 [18-97] years; 866 [55.3%] women among 1565 contacts with sex data) were interviewed; among 1523 contacts with race data, there were 69 Asian individuals (4.2%), 705 Black individuals (43.2%), and 573 White individuals (35.1%), and among 1514 contacts with ethnicity data, there were 202 Hispanic individuals (12.8%) and 1312 individuals (83.4%) who were not Hispanic. Most contacts lived in a household with 2 to 5 people (1123 of 1418 individuals with household data [79.2%]). Of 3324 cases and contacts who completed a questionnaire on unmet social needs, 907 (27.3%) experienced material hardships that would make it difficult for them to isolate or quarantine safely. Such hardship was significantly less common among White compared with Black participants (odds ratio, 0.20; 95% CI, 0.16-0.25). Conclusions and Relevance: These findings demonstrate the feasibility and challenges of implementing a case investigation and contact tracing program at an academic health system. In addition to successfully engaging most assigned COVID-19 cases and close contacts, contact tracers shared health information and material resources to support isolation and quarantine, thus filling local public health system gaps and supporting local pandemic control.

Disadvantage Indices Deployed to Promote Equitable Allocation of COVID-19 Vaccines in the US: A Scoping Review of Differences and Similarities in Design.

This scoping review identifies the construction and defined purpose of disadvantage indices deployed during the initial COVID-19 vaccine rollout.

Factors Influencing Parental and Individual COVID-19 Vaccine Decision Making in a Pediatric Network.

Aspects of the COVID-19 vaccination campaign differed from routine vaccines, including emergency use authorizations, the prioritization of access, and the politicization of messaging. Subsequently, many parents reported lower vaccine confidence relative to routine vaccines, and vaccination coverage stalled below targets. This study aimed to understand parental vaccine decision making and compare COVID-19 versus routine vaccine decision making. We conducted nine virtual focus groups between 25 February 2022-11 March 2022 with parents (n = 41) of the Children's Hospital of Philadelphia's patients, recruited via email and stratified by vaccine hesitancy status (non-hesitant vs. hesitant). Transcripts were analyzed using the vaccine hesitancy matrix domains. Of 41 total participants, 25 (61.0%) were non-hesitant, 16 (39.0%) were hesitant or their children were not up-to-date on adolescent vaccines, and most self-identified as female (95.1%) and White/Caucasian (61.0%). Most participants (87.5%) were fully vaccinated against COVID-19 and many of their first children (n = 26, 63.4%) were vaccinated against influenza. Several themes emerged regarding decision making: individual influences, group influences, vaccine and vaccine program influences, and contextual influences. While some influences were similar for routine and COVID-19 vaccine decision making (e.g., needing evidence-based information), other factors were vaccine- or situation-specific. Building trust requires a multi-faceted concerted effort that involves addressing the complex vaccine decision-making process.

Genomic Analysis of AZD1222 (ChAdOx1) Vaccine Breakthrough Infections in the City of Mumbai.

Background: This manuscript describes the genetic features of SARS-CoV-2 mutations, prevalent phylogenetic lineages, and the disease severity amongst COVID-19-vaccinated individuals in a tertiary cancer hospital during the second wave of the pandemic in Mumbai, India. Methods: This observational study included 159 COVID-19 patients during the second wave of the pandemic from 17th March to 1st June 2021 at a tertiary cancer care centre in Mumbai. The cohort comprised of healthcare workers, staff relatives, cancer patients, and patient relatives. For comparison, 700 SARS-CoV-2 genomes sequenced during the first wave (23rd April to 25th September 2020) at the same centre were also analysed. Patients were assigned to nonvaccinated (no vaccination or <14 days from the 1st dose, n = 92), dose 1(≥14 days from the 1st dose to <14 days from the 2nd dose, n = 29), and dose 2 (≥14 days from the 2nd dose, n = 38) groups. Primary measure was the prevalence of SARS-CoV-2 genomic lineages among different groups. In addition, severity of COVID-19 was assessed according to clinical and genomic variables. Results: Kappa B.1.1671.1 and delta B.1.617.2 variants contributed to an overwhelming majority of sequenced genomes (unvaccinated: 40/92, 43.5% kappa, 46/92, 50% delta; dose 1: 14/29, 48.3% kappa, 15/29, 51.7% delta; and dose 2: 23/38, 60.5% kappa, 14/38 36.8% delta). The proportion of the kappa and delta variants did not differ significantly across the unvaccinated, dose 1, and dose 2 groups (p = 0.27). There was no occurrence of severe COVID-19 in the dose 2 group (0/38, 0% vs. 14/121, 11.6%; p = 0.02). SARS-CoV-2 genomes from all three severe COVID-19 patients in the vaccinated group belonged to the delta lineage (3/28, 10.7% vs. 0/39, 0.0%, p = 0.04). Conclusions: Sequencing analysis of SARS-COV-2 genomes from Mumbai during the second wave of COVID-19 suggests the prevalence of the kappa B.1.617.1 and the delta B.1.627.2 variants among both vaccinated and unvaccinated individuals. Continued evaluation of genomic sequencing data from breakthrough COVID-19 is necessary for monitoring the properties of evolving variants of concern and formulating appropriate immune response boosting and therapeutic strategies.

Prevalence and Sequelae of Cryptococcal Antigenemia in Antiretroviral Therapy-Experienced Populations: An Evaluation of Reflex Cryptococcal Antigen Screening in Botswana.

BACKGROUND: Evidence to inform cryptococcal antigen (CrAg)-screening guidelines among ART-experienced populations is lacking. We performed a study evaluating the utility of reflex CrAg screening in Gaborone, Botswana. METHODS: CD4 count data were collected from the HIV reference laboratory from 2014-2016. CrAg screening was performed on samples with CD4 ≤100 cells/µL beginning January 2015. The proportion of CD4 counts ≤100 cells/µL was determined and the frequency of repeat CrAg testing described. Analyses ascertained the impact of ART status on CrAg prevalence and outcomes, and whether CrAg titers could be used for risk stratification. RESULTS: Overall, 5.6% (3335/59 300) of individuals tested had CD4 ≤100 cells/µL; 2108 samples with CD4 ≤100 cells/µL from 1645 unique patients were CrAg tested. Over half of samples were from ART-experienced individuals: 40.9% (863) on ART and 12.1% (255) defaulters; 22% (463) of CrAg tests were on repeat samples. CrAg prevalence was 4.8% (72/1494; 95% CI, 3.8-6.0%) among outpatients and 21.9% (32/151; 95% CI, 15.3-28.5%) among inpatients. CrAg prevalence rates did not differ by ART status, but 6-month mortality was significantly lower in CrAg-positive individuals on ART at screening. Ten CrAg positives were identified through repeat testing. A CrAg titer cutoff ≥1:80 provided the best discrimination for 6-month survival. CONCLUSIONS: CrAg-positivity rates in an ART-experienced population were comparable to those seen in ART-naive populations. Repeat screening identified individuals who seroconverted to CrAg positivity and were at risk of cryptococcal disease. CrAg titers ≥1:80 can help identify the individuals at highest risk of death for more intensive management.

Impact of school-entry vaccination requirement changes on clinical practice implementation and adolescent vaccination rates in metropolitan Philadelphia.

In 2017, Pennsylvania amended school-entry vaccination requirements including reduction of the provisional period from eight months to the first five days of school and requirement of meningococcal-conjugate vaccine (MCV4) for students entering 12th grade. This cross-sectional study evaluates the impact of these new requirements on clinical practice and vaccination rates among requirement-eligible adolescents within a large pediatric network in metropolitan Philadelphia. We surveyed providers from 24 pediatric primary care facilities across five Southeastern Pennsylvania counties to assess strategies for timely vaccination of children, facilitators and barriers to implementation of these strategies, and attitudes toward the new school vaccine requirements. Vaccination rates post-five-day grace period among eligible 12-18-year-old adolescents were calculated using aggregate electronic health record data and compared pre- and post-policy implementation (2016 vs. 2017) using two-sample tests of proportion. Overall, providers were supportive of the new vaccination requirements and reported that their facilities were equipped to accommodate the increased demand for vaccination visits prior to the beginning of the school year. There were modest increases in Tdap and MCV4 vaccination rates among 12-13-year-old adolescents by mid-September and a significant increase for MCV4 among 17-18-year-old adolescents (p > .001) in all regions. There were also statistically significant increases (p > .001) in MenB and HPV vaccination rates in this older age group. Our results suggest that these amended school-entry vaccination requirements may help improve timely vaccination rates for both required and non-required vaccines, increasing protection among students at the beginning of the school year.

Understanding vaccine knowledge, attitudes, and decision-making through college student interviews.

Objective: We aimed to explore knowledge, attitudes, and beliefs about vaccines required for college-entry and vaccine-related behaviors among college students. Participants: Thirty-three full-time undergraduate students, ≥ 18 years old, enrolled at public (2) and private (3) colleges and universities in metropolitan Philadelphia in fall 2016. Methods: We conducted semistructured interviews, which were double-coded with 5,015 comments overall and 99.3% intercoder reliability (κ = 0.779) using NVivo 11 software. Results: Six key themes emerged: (1) low knowledge about vaccines and requirements; (2) mixed attitudes about required vs. recommended vaccines; (3) high trust in medical professionals; (4) low perceived risk for vaccine-preventable disease outbreaks; (5) substantial parental influence on students' decision-making; and (6) low utilization of Student Health Services. Conclusions: This study revealed lack of knowledge about and low prioritization of vaccination despite overall positive attitudes towards vaccines. Prematriculation education of college students is critical to increasing vaccine knowledge and use.

Perspectives on state vaccine education mandate policy and implementation among public health department officials: a qualitative study.

In response to the increase in non-medical vaccine exemptions (NME), many states have adopted education mandates (EM), required vaccine education for parents requesting NMEs for their school-age children, but these EMs vary greatly in implementation. In order to learn about the administrative aspects of each state's EM, we interviewed fourteen health department officials from nine states with EMs. Interviews were conducted over the phone, transcribed by a professional transcription service, and double-coded using NVivo 12 by two members of the study staff. The coding resulted in 3698 comments overall, 98.5% inter-coder reliability, and a κ statistic of 0.691. We found no consistent format for content delivery, and methods used included in-person dialogs, web-based education, and video modules. Content of the education is not standardized, and education length ranges from 15 to 60 minutes. Four major themes about the EM policies emerged: (1) the use of EMs to eliminate "convenience exemptions;" (2) the importance of health department communication with health-care providers; (3) facilitators and barriers to implementation; and (4) the positive recommendation for other states to adopt EM policies. We concluded that current EM implementation varies greatly, but officials in states which have adopted EMs for parents requesting NMEs for school-entry vaccinations overwhelmingly recommend other states to adopt them as well. Key features of successful programs may include conversations with parents requesting NMEs and strong communication channels with health-care providers. Systematic tracking of vaccine status after exemption requests and education is necessary to quantitatively determine the effectiveness of EM programs.

Student health administrator perspectives on college vaccine policy development and implementation.

BACKGROUND: Immunization policies at colleges and universities differ greatly for many reasons, including prior experience with disease outbreaks and state immunization requirements. Few studies comprehensively explore the range of factors that influence the development of college vaccine policies or facilitators and barriers to their implementation. OBJECTIVE: To explore the perceptions and decision-making process that influence college vaccine policy development and implementation from the perspective of student health administrators. METHODS: This qualitative study used semi-structured interviews with student health administrators (N = 10) from ten U.S. colleges and universities purposefully sampled by school type (public vs. private) and geographic region. A descriptive codebook was developed from the interview guide, and each interview was double-coded using NVivo 11 software (κ = 0.87; inter-observer reliability = 99.4%). RESULTS: We coded 5785 phrases. Administrators positively viewed their institutions' vaccine requirements, but some expressed concerns about the acceptance of philosophical and religious exemptions. They noted that students were generally ambivalent towards vaccine requirements, and while students recognized the benefits of vaccination, they did not prioritize immunizations. All administrators cited reliance on governmental and professional organizations as well as state regulations for decisions regarding vaccine requirements and recommendations at their institutions. Partnerships with other school departments, pharmaceutical companies, immunization coalitions, and healthcare providers were frequently cited as facilitators of college vaccine programs. Costs of purchasing, storing, and tracking vaccines were identified as major barriers. CONCLUSIONS: We identified key themes that can be evaluated in subsequent studies to identify factors associated with successful implementation of university immunization programs and inform initiatives to increase vaccine acceptance and optimize immunization rates on college and university campuses.

Evaluating Variability in Immunization Requirements and Policy Among U.S. Colleges and Universities.

OBJECTIVES: To evaluate variation in vaccine requirements, recommendations, and enforcement strategies among U.S. four-year colleges and universities. METHODS: We conducted a cross-sectional study abstracting information from Web sites among a sample of 216 four-year colleges and universities from all 50 states and District of Columbia. Our primary outcomes of interest included: type and number of vaccines required for school entry, vaccines recommended by schools for students, and vaccines supplied through student health services. Covariates of interest included: school type, region, school size, mention of American College Health Association recommendations, presence of an accredited health center, mention of state requirements, presence of an enforcement strategy, and exemption stringency of the state in which the school was located. RESULTS: Almost all (94%) schools required at least one vaccine for school entry, and 48% required three or more vaccines. The most commonly required vaccines were measles, mumps, and rubella (88.4%) and meningococcal vaccine (51.9%). All schools required the same vaccines included in state requirements but 65% also required additional vaccines. Most schools (67.1%) used registration hold to enforce requirements, while 14.8% restricted students from campus housing and 2.8% dismissed noncompliant students. Seventeen percent of schools had no published enforcement strategies. A higher proportion of private compared to public universities required three or more vaccines (57% vs. 37.3%, p = .014). CONCLUSIONS: While most schools have immunization requirements, there is significant variation in number and type of vaccines required. This suggests potential inconsistent uptake of recommended vaccines for college students and underlies the need to characterize facilitators and barriers to immunization program implementation on college campuses.

HIV-1 latent reservoir size and diversity are stable following brief treatment interruption.

BACKGROUND: The effect of a brief analytical treatment interruption (ATI) on the HIV-1 latent reservoir of individuals who initiate antiretroviral therapy (ART) during chronic infection is unknown. METHODS: We evaluated the impact of transient viremia on the latent reservoir in participants who underwent an ATI and at least 6 months of subsequent viral suppression in a clinical trial testing the effect of passive infusion of the broadly neutralizing Ab VRC01 during ATI. RESULTS: Measures of total HIV-1 DNA, cell-associated RNA, and infectious units per million cells (IUPM) (measured by quantitative viral outgrowth assay [QVOA]) were not statistically different before or after ATI. Phylogenetic analyses of HIV-1 env sequences from QVOA and proviral DNA demonstrated little change in the composition of the virus populations comprising the pre- and post-ATI reservoir. Expanded clones were common in both QVOA and proviral DNA sequences. The frequency of clonal populations differed significantly between QVOA viruses, proviral DNA sequences, and the viruses that reactivated in vivo. CONCLUSIONS: The results indicate that transient viremia from ATI does not substantially alter measures of the latent reservoir, that clonal expansion is prevalent within the latent reservoir, and that characterization of latent viruses that can reactivate in vivo remains challenging. TRIAL REGISTRATION: ClinicalTrials.gov NCT02463227FUNDING. Funding was provided by the NIH.

HIV-1 and hepatitis C virus selection bottleneck in Chinese people who inject drugs.

OBJECTIVES: For both HIV-1 and hepatitis C virus (HCV), assessing the stringency of the transmission process is a scientific priority. Enumerations of transmitted/founder (TF) viruses have shown a strict transmission bottleneck in sexual transmission of HIV-1 and a wide range in the multiplicity of infection in HCV. Here, we aim to determine the stringency of parenteral transmission for HIV-1 and HCV in people who inject drugs (PWID). DESIGN: We used molecular sequencing and several complementary analyses to enumerate the TF HIV-1 and HCV variants in a well described cohort of PWID in Xinjiang, China. METHODS: We performed single genome sequencing of HIV-1 env and 5' half HCV genomes, then applied phylogenetic analysis and validated models of early virus diversification to enumerate TF viruses in 60 PWID. We used multivariate analysis to determine correlates of multivariant transmission (MVT). RESULTS: We generated 1070 env region sequences from 33 HIV-1 early infected individuals and 773 5' half region sequences from 27 HCV early infected individuals. We found rates of MVT of 39 and 54%, respectively, for HIV-1 and HCV, with a limited range in the number of TF viruses in both infections. Behavioural characteristics suggested high-risk injection practices and lower risk sexual practices; we did not find an association between any specific behaviours and MVT. CONCLUSION: MVT is frequent in parenteral transmission of both HIV-1 and HCV in Xinjiang PWID, indicating a less stringent transmission process than sexual transmission.