Albert Vollaard

Dr. Albert Vollaard

orcid

Research Focus & Metrics

Academic Career Length

13Years (2014-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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1 May 2017 in European Journal of Cancer
Verified
Journal Article
Closed access
AVAlbert Vollaard
Albert Vollaard
ISImke Schreuder
Imke Schreuder
LSLizzy Slok-Raijmakers
Lizzy Slok-Raijmakers
WOWim Opstelten
Wim Opstelten
GRGuus Rimmelzwaan
Guus Rimmelzwaan
HGHans Gelderblom
Hans Gelderblom

1 December 2020 in eClinicalMedicine
Verified
Journal Article
Open access
HGHannah Garcia Garrido
Hannah Garcia Garrido
JSJenny L. Schnyder
Jenny L. Schnyder
MTMichael WT Tanck
Michael WT Tanck
AVAlbert Vollaard
Albert Vollaard
RSRené Spijker
René Spijker
AGAbraham Goorhuis
Abraham Goorhuis
The objective of this systematic review and meta-analysis was to summarise the literature regarding the immunogenicity of pneumococcal conjugate vaccines (PCV) and pneumococcal polysaccharide vaccines (PPSV) in adult people living with HIV (PLWH) in the era of advanced combination antiretroviral therapy (cART). The systematic review protocol was published online (PROSPERO ID: CRD 42020153137). We searched Medline (Ovid), EMBASE (Ovid), and the Global Health Library for publications from 2000 to June 11, 2020. We included all studies in adult PLWH that reported vaccine immunogenicity outcomes. The primary outcome was seroconversion rate (SCR) after PCV, PPSV and PCV/PPSV combined. For random-effects meta-analysis, we included studies defining SCR as a ≥ 2-fold increase in IgG from baseline, and reporting SCR for serotypes 6B, 14, or overall SCR, 1–3 months after vaccination. Our search identified 1597 unique studies, of which 115 were eligible for full-text assessment. Of these, 39 met the inclusion criteria (11 RCTs; 28 cohort studies). A high degree of heterogeneity was observed. Nineteen studies were included in the meta-analysis. Pooled overall SCRs were 42% (95% CI 30–56%), 44% (95% CI 33–55%) and 57% (95% CI 50–63%) for PLWH who received PPSV, PCV or a combination of PCV/PPSV, respectively. Compared to PPSV alone, a combination of PCV/PPSV yielded higher SCRs (OR 2.24 95% CI 1.41- 3.58), whereas we did not observe a significant difference in SCR between PCV and PPSV23 alone. There were no statistically significant differences in geometric mean post-vaccination antibody concentrations between vaccination schedules. Vaccination at higher CD4 cell counts improved immunogenicity in 8/21 studies, especially when PCV was administered. No studies assessed the long-term immunogenicity of PCV followed by PPSV23. Quality of evidence ranged from poor (n = 19) to good quality (n = 7). A limited number of pneumococcal serotypes was assessed in the majority of studies. We show that the recommended immunisation schedule consisting of a combination of PCV13/PPSV23, is immunogenic in PLWH in the era of advanced cART. However, the durability of this vaccination schedule remains unknown and must be addressed in future research. Vaccination with PCV should be delayed until immunological recovery (CD4>200) in recently diagnosed PLWH for optimal immunogenicity. The evidence gathered here supports wide implementation of the combination of PCV/PPSV23 for all PLWH. We recommend reassessment of this strategy once higher-valent PCVs become available. HMGG is funded by a public research grant of ZonMw (project number 522004005).

17 May 2022 in Vaccines
Verified
Journal Article
Open access
PDF file
HGHannah Garcia Garrido
Hannah Garcia Garrido
AVAlbert Vollaard
Albert Vollaard
GDGeert R. D’Haens
Geert R. D’Haens
PSPhyllis I. Spuls
Phyllis I. Spuls
FBFrederike J. Bemelman
Frederike J. Bemelman
AGAbraham Goorhuis
Abraham Goorhuis
Immunosuppressive therapy increases the risk of pneumococcal disease. This risk can be mitigated by pneumococcal vaccination. The objective of this study was to investigate the immunogenicity of the 13-valent pneumococcal conjugate vaccine (PCV13), followed by the 23-valent pneumococcal polysaccharide vaccine (PPSV23), in adults with and without immunosuppressive therapy. We performed a prospective cohort study among adults using conventional immunomodulators (cIM), biological immunomodulators (bIM), combination therapy, and controls during 12 months. The primary outcome was seroprotection, defined as the proportion of patients with a postimmunization IgG concentration of ≥1.3 µg/mL for at least 70% (17/24) of the serotypes of PCV13 + PPSV23. We included 214 participants. For all 24 vaccine serotypes, IgG levels increased significantly in both treatment subgroups and controls, with peak seroprotection rates of 44% (combination therapy), 58% (cIM), 57% (bIM), and 82% (controls). By month 12, seroprotection had decreased to 24%, 48%, 39%, and 63%, respectively. Although pneumococcal vaccination with PCV13 + PPSV23 was immunogenic in all treatment groups, impaired vaccination responses were observed in patients using immunosuppressive medication. Apart from the obvious recommendation to administer vaccines before such medication is started, alternative vaccination strategies, such as additional PCV13 doses or higher-valent pneumococcal vaccines, should be investigated.

9 December 2024 in Vaccines
Verified
Journal Article
Open access
PDF file
ELElsemieke te Linde
Elsemieke te Linde
MHMarjolein P. M. Hensgens
Marjolein P. M. Hensgens
AVAlbert Vollaard
Albert Vollaard
AVAnnelies Verbon
Annelies Verbon
ABAnke H. W. Bruns
Anke H. W. Bruns
Background: In recent decades, the number of immunocompromised patients (ICPs) has increased significantly. ICPs have an impaired immune system, making them susceptible to complicated infections. To protect them from infections, ICPs are eligible to receive several medically indicated vaccines. To obtain insight into the uptake of these medically indicated vaccines, we determined the coverage of these vaccines in ICPs. Methods: This observational cohort study was conducted at the University Medical Centre Utrecht, the Netherlands, from September 2021 to April 2022. All adult ICPs admitted for COVID-19 were asked to complete a questionnaire on their vaccination history (pneumococcal, herpes zoster, human papillomavirus vaccination, influenza, and COVID-19 vaccines) and history of vaccine-preventable infections. In addition, patients’ vaccination history was reviewed in medical files. Results: A total of 115 patients completed the questionnaire and were included. Although all patients had an indication for pneumococcal vaccination, only 22 received it (19%). Coverage for herpes zoster was low (1%, 1/106 eligible patients). Coverage for human papillomavirus vaccination (HPV) was also low (40%, two out of five eligible patients). In contrast, 92% of patients received vaccination against SARS-CoV-2, and 77% of patients received seasonal influenza vaccination. Conclusions: Although coverage for influenza and COVID-19 vaccination was high in ICPs, coverage for other medically indicated vaccines was low. Identifying which factors contributed to high COVID-19 and influenza vaccine uptake can help to improve vaccination rates for the other recommended vaccines. Clear guidelines for clinicians and the removal of organizational obstacles are needed to improve vaccination coverage.

12 October 2023
Verified
Journal Article
Closed access
AVAlbert Vollaard
Albert Vollaard
ESEdwin N E Slok
Edwin N E Slok
PDPaul R M van Dijkman
Paul R M van Dijkman
ODOlaf M Dekkers
Olaf M Dekkers
GGGeert H Groeneveld
Geert H Groeneveld

12 March 2018 in Bijblijven
Verified
Journal Article
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PDF file
AVAlbert Vollaard
Albert Vollaard