Publications by authors named "Troy Kemp"
HPV16/18 antibodies 16-years after single dose of bivalent HPV vaccination: Costa Rica HPV vaccine trial.
J Natl Cancer Inst Monogr
November 2024
Background: The Costa Rica HPV Vaccine Trial provided initial evidence that 1 dose of the bivalent human papillomavirus (HPV) vaccine induces stabilizing antibody levels that may provide extended protection against HPV-16/18 infections. We report antibody seropositivity and stability 11 to 16 years after vaccination.
Methods: We invited a random subset of Costa Rica HPV Vaccine Trial participants (n = 398) who had received 3 doses and all women (n = 203) who had received 1 dose at 18 to 25 years of age to follow-up visits 11, 14, and 16 years after vaccination.
Article Synopsis
- * A study involving 82 patients with gallbladder dysplasia and 1843 with gallstones found that NSAID use was inversely associated with gallbladder dysplasia, suggesting lower risk for users (OR: 0.48).
- * Eight immune-related proteins showed an inverse association with dysplasia, indicating that further research is needed to explore the role of inflammation and NSAIDs in gallbladder health, ideally in future studies involving asymptomatic individuals.
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- Serology testing is vital for assessing the effectiveness of COVID-19 vaccines and detecting past infections by measuring antibodies against SARS-CoV-2.
- This study validated four laboratory-developed serology tests for antibodies (IgG and IgM) against Spike and Nucleocapsid proteins, ensuring they met strict Clinical and Laboratory Standards Institute (CLSI) guidelines for reliability.
- Results showed good linearity and precision across the tests, demonstrating their validity for identifying levels of antibodies, which is crucial for ongoing COVID-19 research and management.
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- The study evaluated the reproducibility of enzyme-linked immunosorbent assays (ELISAs) that measure various anti-HPV immunoglobulin isotypes (IgG1, IgG3, IgA, and IgM) in serum samples from participants vaccinated with the bivalent HPV vaccine.
- Results showed low levels of IgG2 and IgG4, with varying coefficients of variation (CVs) indicating differences in reproducibility across technicians and days; IgM had higher CVs compared to the other isotypes.
- The findings confirmed that the ELISAs are reliable for detecting HPV16 antibodies, with all isotype antibodies showing high intraclass correlation coefficients (ICCs) and significant correlations between
Previously established World Health Organization (WHO) International Standards (IS) for anti-HPV16 and HPV18 antibodies are used to harmonize results across human papillomavirus (HPV) serology assays. Here, we present an international collaborative study to establish ISs for antibodies against HPV6 (NIBSC code 19/298), HPV11 (20/174), HPV31 (20/176), HPV33 (19/290), HPV45 (20/178), HPV52 (19/296) and HPV58 (19/300). The candidate standards were prepared using sera from naturally infected individuals.
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- SARS-CoV-2 serology is important for assessing COVID-19 vaccine effectiveness and immune response, but factors like tube type and anticoagulant can affect results.
- The study found no significant differences in antibody levels based on tube type; however, tubes with anticoagulants sodium citrate and ACD showed lower antibody concentrations, which were mostly adjusted after considering dilution factors.
- There were noticeable differences in IgG avidity between plasma and serum, suggesting that plasma treated with anticoagulant cannot be considered interchangeable with serum for certain assays, warranting further exploration.
Article Synopsis
- - Neutralizing antibodies (NAbs) are crucial for vaccine protection against HPV, but the necessary levels for effective protection are still unknown.
- - The study introduces a new multiplex bead-based immunoassay that can efficiently analyze antibody responses to multiple oncogenic HPV types found in the nonavalent HPV vaccine.
- - This new assay is faster and uses fewer samples than the traditional HPV pseudovirion-based neutralization assay (PBNA), showing strong agreement with NAb results from the PBNA.
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- SARS-CoV-2 vaccination leads to changes in antibody levels and characteristics, which can influence protection against infection.
- After the initial vaccine series, IgG levels decrease over time while antibody avidity (binding strength) increases; however, this trend is reversed after a third booster dose, which boosts both IgG levels and avidity.
- Comparison between the two mRNA vaccines shows that one (BNT162b2) results in higher antibody avidity than the other (mRNA-1273) six months after the third dose.
Article Synopsis
- The World Health Organization recommends HPV vaccination schedules for individuals aged 9-20 years, including studies on single-dose efficacy, particularly focusing on a Phase 3 trial of the Cecolin® vaccine in low- and middle-income countries.
- In this trial, 1,025 girls in Bangladesh and Ghana received various dosing schedules of Cecolin or Gardasil® to evaluate immunological responses and safety after vaccination.
- Interim results showed that the Cecolin vaccine was non-inferior to Gardasil, with 100% seropositivity one month after the second dose, and over 96% seropositivity six months after one dose, indicating strong immunogenicity and comparable safety profiles between the two vaccines.
Article Synopsis
- - The KEN SHE trial demonstrated over 97% efficacy for a single-dose HPV vaccine against HPV16 and HPV18 infections in Kenyan women over 36 months.
- - The DoRIS trial involved 930 Tanzanian girls aged 9-14, examining antibody responses from one, two, or three doses of either 2-valent (Cervarix) or 9-valent (Gardasil-9) vaccines, finding comparable or higher antibody levels at 24 months compared to the KEN SHE participants.
- - Results indicated that a single dose of either HPV vaccine effectively induced immune responses in young girls, suggesting it may be sufficient for protection, similar to the responses seen in older women who had received a single
The COVID-19 pandemic led to the rapid development of tests to diagnose SARS-CoV-2 infection and ascertain the prevalence of infection, along with the formulation of various treatments and vaccines. Globally, over 220 anti-SARS-CoV-2 serological assays have been developed for laboratory use, and many of these assays are currently used to assess immune responses against SARS-CoV-2. However, because these assays were independently developed by different manufacturers with different target antigens, immunoglobulin detection, technologies, and data reporting approaches, the results are not directly comparable, making it challenging to draw conclusions regarding immune responses at the population level.
View Article and Find Full Text PDFCOVID-19 has highlighted challenges in the measurement quality and comparability of serological binding and neutralization assays. Due to many different assay formats and reagents, these measurements are known to be highly variable with large uncertainties. The development of the WHO international standard (WHO IS) and other pool standards have facilitated assay comparability through normalization to a common material but does not provide assay harmonization nor uncertainty quantification.
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- * The panel consists of 80 deidentified samples and was tested using two types of assays across 10 labs in 7 countries, focusing on accuracy and monitoring responses for up to 9 HPV types.
- * Results showed high accuracy, with 74 out of 80 samples achieving 100% accuracy, while sensitivity and specificity rates for the assays were generally strong, indicating reliable performance in HPV serology testing for clinical trials.
Article Synopsis
- - The HPV Serology Laboratory is spearheading a global initiative focused on standardizing and harmonizing how serology assays are used to evaluate immune responses to HPV vaccines.
- - This standardization is crucial due to the rise of immunobridging trials that depend on serology data for the approval of new vaccine schedules and formulations.
- - Established in 2017, the initiative aims to facilitate data comparisons across different vaccines and studies, promoting faster adoption of new vaccines and their applications.
Article Synopsis
- A phase IIa trial investigated the effectiveness of a single-dose nonavalent HPV vaccine (Gardasil9) on antibody responses among 201 healthy children aged 9 to 11.
- Results showed that antibody levels for HPV16 and HPV18 peaked at 6 months, remained stable for 24 months, and responded positively to a delayed booster dose at 30 months.
- The study suggests that a single-dose vaccination could simplify HPV vaccination programs globally, yet it calls for further research on long-term antibody stability and overall health benefits.
Article Synopsis
- This study compares the immune responses of two mRNA vaccines (mRNA-1273 and BNT162b2) against SARS-CoV-2 to natural infection by measuring anti-Spike antibody levels and avidity in serum samples from different age groups.
- Results showed that both vaccines produced higher antibody levels and avidity than natural infection, with mRNA-1273 demonstrating superior antibody levels four months post-vaccination.
- Additionally, mRNA-1273 induced greater avidity than BNT162b2 at one month, though this was only significantly maintained in the younger age group by four months.
Article Synopsis
- The COVID-19 pandemic created a rush for accurate tests to measure antibodies against SARS-CoV-2, leading to many assays being developed without strict quality control, resulting in varied performance levels.
- This study evaluates the reliability and effectiveness of different serology assays, including commercial and in-house tests, and supports the use of the WHO International Standard as a way to harmonize results across different methods.
- Findings suggest that while commercial assays are highly specific and in-house assays are sensitive, binding immunoassays can be a practical alternative to more complex neutralization tests, and all assay types perform well after standardization, underscoring that robust serology tests are available for better understanding antibody responses.
Article Synopsis
- * The assay's performance was assessed using samples from both negative controls and PCR-confirmed cases, confirming its accuracy, precision, and lack of interference between different antigens.
- * Results are reported in terms of antibody concentrations aligned with WHO standards, making this assay an effective tool for studying immunity and vaccine responses in the context of SARS-CoV-2.
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- The HPV Serology Laboratory at the Frederick National Laboratory for Cancer Research is collaborating with the scientific community to standardize HPV serology assays, which are crucial for regulatory approvals of vaccines.
- A virtual meeting took place on June 29-30, 2021, to assess progress on this standardization initiative and address scientific gaps.
- Key topics discussed included assay standardization, calibration procedures, cut-off values, ongoing immunobridging trials, and challenges in standardizing HPV serology practices.
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- The SARS-CoV-2 pandemic created a need for precise serological testing to assess immunity from infections and vaccines, leading to the development of a U.S. serology standard.
- The Frederick National Laboratory for Cancer Research established this standard and calibrated it against a WHO international standard to ensure consistent results in serology assays.
- A study involving eight laboratories demonstrated that using the U.S. serology standard significantly reduced variability in test results, making it a key resource for harmonizing data globally.
Article Synopsis
- The study investigates the effectiveness of administering one dose of HPV vaccine compared to historical studies that showed high efficacy with one dose over an 11-year period against HPV16 and HPV18.
- Researchers conducted the Dose Reduction Immunobridging and Safety Study (DoRIS) in Tanzania involving girls aged 9-14 years, randomly assigning them to receive one, two, or three doses of either a 2-valent or 9-valent HPV vaccine.
- The primary goal was to analyze the antibody responses after one dose and determine if these responses were comparable to those found in previous trials, applying statistical methods to assess non-inferiority of immune responses.
Background: An estimated 15% of girls aged 9-14 years worldwide have been vaccinated against human papillomavirus (HPV) with the recommended two-dose or three-dose schedules. A one-dose HPV vaccine schedule would be simpler and cheaper to deliver. We report immunogenicity and safety results of different doses of two different HPV vaccines in Tanzanian girls.
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- The National Cancer Institute established the Serological Sciences Network (SeroNet) in October 2020 to study immune responses to COVID-19 and enhance serological testing technologies.
- SeroNet involves 25 research institutions collaborating on COVID-19 serological assays, including developing and sharing assay procedures and harmonization plans.
- A structured approach was taken to calibrate various serological assays to reference standards, resulting in a wide range of developed assays that will allow for consistent reporting and future data comparisons across studies.
Article Synopsis
- - The HPV vaccine demonstrates long-lasting effectiveness and stable antibody levels even after just one dose, as shown in a study tracking HPV16 antibody avidity over 11 years among women in Costa Rica who received either one or three vaccine doses.
- - Women who received only one dose had lower HPV16 antibody avidity compared to those who received three doses, but both groups showed similar patterns of increased avidity in the first three years, remaining stable for the subsequent eight years.
- - The study found that women who were seropositive for HPV16 at the time of vaccination had lower antibody avidity than seronegative women, but both groups showed similar vaccine efficacy against HPV16 infections, suggesting that even lower avidity levels can still offer