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Objectives: Pneumococcal disease (PD), caused by S. pneumoniae, is a serious global health issue, primarily for adults over 65, due to its high mortality and morbidity rates. Recently, broader-serotype vaccines have been introduced to cope with tremendous hospital costs and decreasing quality of life. Our study aims to systematically review the cost-effectiveness of current PCVs (pneumococcal conjugate vaccines) and PPVs (pneumococcal polysaccharide vaccine) from 2018 to April 2024. Methods: Articles were identified through PubMed, Embase, and Cochrane. Key outcomes include an improved incremental cost-effectiveness ratio (ICER) and quality-adjusted life-years (QALY), with the article's quality assessed via the Consolidated Health Economic Evaluation Reporting Standards 2022 (CHEERS 2022). In total, 23 studies were included, with 22 studies of high quality and 1 of moderate quality. Results: These articles showed that PCV20 was the most cost-effective option compared with other vaccines, including PPV23, PCV13, PCV15, and PCV15/PPV23, for both young and older adults, regardless of risk factors. PCV20, when used alone, saved greater costs than PCV20, followed by PPV23. Conclusions: For countries applying lower-valency vaccines, switching to PCV20 as a single regimen would be the most beneficial for averting pneumococcal cases and reducing costs in adults aged 18–64 and over 65. [ABSTRACT FROM AUTHOR]

The prevalence of hepatitis E virus (HEV) in the Vietnamese population remains underestimated. The aim of the present study was to investigate the seroprevalence of HEV IgG/IgM antibodies and the presence of HEV RNA in blood donors as a part of epidemiological surveillance for transfusion-transmitted viruses. Serum samples from blood donors (n = 553) were analysed for markers of past (anti-HEV IgG) and recent/ongoing (anti-HEV IgM) HEV infections. In addition, all serum samples were subsequently tested for HEV RNA positivity. The overall prevalence of anti-HEV IgG was 26.8% (n = 148/553), while the seroprevalence of anti-HEV IgM was 0.5% (n = 3/553). Anti-HEV IgG seroprevalence in male and female donors was similar (27.1% and 25.5%, respectively). A higher risk of hepatitis E exposure was observed with increasing age. None of the blood donors were HEV RNA positive, and there was no evidence of HEV viraemia. Although the absence of HEV viraemia in blood donors from Northern Vietnam is encouraging, further epidemiological surveillance in other geographical regions is warranted to rule out transfusion-transmitted HEV. [ABSTRACT FROM AUTHOR]

Osteoarthritis (OA) is the degeneration of cartilage in joints that results in bones rubbing against each other; it causes uncomfortable symptoms such as pain, swelling, and stiffness and can lead to disability. It usually occurs in the elderly and causes a large medical burden. The aim of this study is to evaluate the cost-effectiveness between the standard treatment for osteoarthritis and standard treatment with added crystalline glucosamine sulfate at various stages. Markov analysis modeling was applied to evaluate the effect of both adding glucosamine compared to standard treatment from a societal perspective during whole patients' lifetimes. Data input was collected from reviews in previous studies. The outcome was measured in quality-adjusted life years (QALYs), and the Incremental Cost-Effectiveness Ratio (ICER) from a societal perspective was applied with 3% and discounted for all costs and outcomes. One-way analysis via the Tornado diagram was performed to investigate the change in factors in the model. In general, adding glucosamine into the standard treatment proved to be more cost-effective compared to the standard treatment. Particularly, the early-stage addition of glucosamine in the treatment was cost-effective compared to the post-stage addition of glucosamine. The addition of supplementing crystalline glucosamine sulfate to the whole regimen at any stage was cost-effective at the willingness-to-pay (WTP) threshold. [ABSTRACT FROM AUTHOR]

Occult hepatitis B infection (OBI) is characterized by the presence of low levels of hepatitis B virus (HBV) DNA and undetectable HBsAg in the blood. The prevalence of OBI in blood donors in Asia ranges from 0.013% (China) to 10.9% (Laos), with no data available from Vietnam so far. We aimed to investigate the prevalence of OBI among Vietnamese blood donors. A total of 623 (114 women and 509 men) HBsAg-negative blood donors were screened for anti-HBc and anti-HBs by ELISA assays. In addition, DNA from sera was isolated and nested PCR was performed for the HBV surface gene (S); a fragment of the S gene was then sequenced in positive samples. The results revealed that 39% (n = 242) of blood donors were positive for anti-HBc, and 70% (n = 434) were positive for anti-HBs, with 36% (n = 223) being positive for both anti-HBc and anti-HBs. In addition, 3% of blood donors (n = 19) were positive for anti-HBc only, and 34% (n = 211) had only anti-HBs as serological marker. A total of 27% (n = 170) were seronegative for any marker. Two of the blood donors (0.3%) were OBI-positive and sequencing revealed that HBV sequences belonged to HBV genotype B, which is the predominant genotype in Vietnam. [ABSTRACT FROM AUTHOR]

Knowledge of the clinical presentation of central nervous system (CNS) infections and the causative pathogens is crucial for appropriate diagnosis and rapid initiation of appropriate treatment to prevent severe neurological sequelae. The aim of this study is to understand the aetiology of CNS infections based on the clinical presentation of Vietnamese patients. A prospective hospital-based cohort study was conducted between May 2014 and May 2017. We screened 137 patients with clinically suspected CNS infection for fungal, bacterial and viral pathogens using their cerebrospinal fluid (CSF) and blood cultures. In addition, DNA or RNA extracted from CSF samples were subjected to nucleic acid testing (NAT) with a selective panel of bacterial, viral and fungal pathogens. At least one pathogen could be detected in 41% (n = 56) of the patients. The main pathogens causing CNS infections were Streptococcus suis (n = 16; 12%) and Neisseria meningitidis (n = 9; 7%), followed by Herpes simplex virus 1/2 (n = 4; 3%) and Klebsiella pneumoniae (n = 4; 3%). Other pathogens were only identified in a few cases. Patients with bacterial CNS infections were significantly older, had a worse outcome, a lower Glasgow Coma Scale (GCS), a higher rate of speech impairment and neck stiffness than patients with viral or tuberculous CNS infections. In northern Vietnam, adults are mostly affected by bacterial CNS infections, which have a severe clinical course and worse outcomes compared to viral or tuberculous CNS infections. Clinicians should be aware of the regional occurrence of pathogens to initiate rapid and appropriate diagnosis and treatment. [ABSTRACT FROM AUTHOR]

Aim: The aim of the present study is to compare the performance of 16S rRNA Nanopore sequencing and conventional culture in detecting infectious pathogens in patients with suspected meningitis in a resource-limited setting without extensive bioinformatics expertise. Methods: DNA was isolated from the cerebrospinal fluid (CSF) of 30 patients with suspected bacterial meningitis. The isolated DNA was subjected to 16S sequencing using MinION™. The data were analysed in real time via the EPI2ME cloud platform. The Nanopore sequencing was done in parallel to routine microbiological diagnostics. Results: Nanopore sequencing detected bacterial pathogens to species level in 13 of 30 (43%) samples. CSF culture showed 40% (12/30) positivity. In 21 of 30 patients (70%) with suspected bacterial meningitis, both methods yielded concordant results. About nine of 30 samples showed discordant results, of these five were false positive and four were false negative. In five of the culture negative results, nanopore sequencing was able to detect pathogen genome, due to the higher sensitivity of the molecular diagnostics. In two other samples, the CSF culture revealed Cryptococcus neoformans and Streptococcus pneumoniae, which were not detected by Nanopore sequencing. Overall, using both the cultures and 16S Nanopore sequencing, positivity rate increased from 40% (12/30) to 57% (17/30). Conclusion: Next-generation sequencing could detect pathogens within six hours and could become an important tool for both pathogen screening and surveillance in low- and middle-income countries (LMICs) that do not have direct access to extensive bioinformatics expertise. [ABSTRACT FROM AUTHOR]

Background: In pregnant women with gestational diabetes mellitus (GDM), insulin resistance (IR) increases the risk of developing manifest type 2 diabetes mellitus and is associated with complications in both mother and fetus. Objectives: This research aimed to evaluate the associations between IR evaluated by 3 indices (namely updated homeostasis model assessment model (HOMA2), QUICKI, and McAuley's index) and the diabetes risk factors and the fetal growth indices in Vietnamese women with GDM. Methods: A cross-sectional descriptive study was conducted on 370 women with GDM and 40 healthy pregnant women from January 2015 to May 2019. IR was calculated by HOMA2 (HOMA2-IR), QUICKI, and McAuley's index. Fetal anthropometric measurements were assessed via ultrasound which was performed and interpreted by ultrasound experts. Results: In the simple regression analysis, McAuley's index illustrated had statistically significant correlations to the highest number of risk factors of diabetes mellitus compared with HOMA2-IR and QUICKI indices. Moreover, McAuley's index correlated statistically significantly to the highest number of fetal ultrasound measurements factors such as including biparietal diameter (BPD) (r = −0.271, P <.001), head circumference (HC) (r = −0.225, P <.001), abdominal circumference (AC) (r = −0.214, P <.001), femur length (FL) (r = −0.231, P <.001), estimated fetal weight (EFW) (r = −0.239, P <.001) and fetal estimated age (r = −0.299, P <.001). In the multivariable analysis, the McAuley's index contributed the greatest to AC (Standardized B of −0.656, P <.001). Conclusion: The McAuley's index was significantly associated with a higher number of more risk factors for diabetes mellitus as well as fetal ultrasound sonography findings measurements than compared with HOMA2-IR and QUICKI indices. [ABSTRACT FROM AUTHOR]

Infections with HEV in low- and middle-income countries (LMICs) are associated with increased rates of preterm birth, miscarriage, and stillbirth. The aim of the present study was to investigate HEV infections in pregnant women and the possibility of mother-to-child transmission, and associated outcomes. A total of 183 pregnant women in their third trimester were recruited and followed until delivery. Anti-HEV IgG and IgM were determined via enzyme-linked immunosorbent assay (ELISA), and HEV nucleic acids were detected in stool and cord blood samples. HEV genotypes were identified by Sanger sequencing, and phylogenetic analyses were performed. Mother-to-child transmission and associated adverse outcomes were not observed. Only 2% of patients (n = 4/183) tested positive for anti-HEV IgM, and 8% (n = 14/183) tested positive for anti-HEV IgG antibodies. Cord blood (n = 150) analysis showed that there was no IgM detected, while 4% (n = 6/150) tested positive for anti-HEV IgG, which was consistent with mothers testing positive for anti-HEV IgG. Nucleic acid tests for HEV RNA yielded 2% (n = 4/183) from the serum and stool of pregnant women, and none from cord blood. The HEV isolates belonged to the genotype HEV-3a, with 99% homology with humans and 96% with pigs. No association was found between the risk of HEV infection and pregnancy outcomes or HEV transmission from mother to child. HEV-3 infections of zoonotic origin in pregnancy might have eventually resolved without complications. [ABSTRACT FROM AUTHOR]

Hepatitis delta virus (HDV) coinfection will additionally aggravate the hepatitis B virus (HBV) burden in the coming decades, with an increase in HBV-related liver diseases. Between 2018 and 2019, a total of 205 HBV patients clinically characterized as chronic hepatitis B (CHB; n = 115), liver cirrhosis (LC; n = 21), and hepatocellular carcinoma (HCC; n = 69) were recruited. HBV surface antigen (HBsAg), antibodies against surface antigens (anti-HBs), and core antigens (anti-HBc) were determined by ELISA. The presence of hepatitis B viral DNA and hepatitis delta RNA was determined. Distinct HBV and HDV genotypes were phylogenetically reconstructed and vaccine escape mutations in the "a" determinant region of HBV were elucidated. All HBV patients were HbsAg positive, with 99% (n = 204) and 7% (n = 15) of them being positive for anti-HBc and anti-HBs, respectively. Anti-HBs positivity was higher among HCC (15%; n = 9) compared to CHB patients. The HBV-B genotype was predominant (65%; n = 134), followed by HBV-C (31%; n = 64), HBV-D, and HBV-G (3%; n = 7). HCC was observed frequently among young individuals with HBV-C genotypes. A low frequency (2%; n = 4) of vaccine escape mutations was observed. HBV-HDV coinfection was observed in 16% (n = 33) of patients with the predominant occurrence of the HDV-1 genotype. A significant association of genotypes with alanine aminotransferase (ALT) and aspartate aminotransferase (AST) enzyme levels was observed in HBV monoinfections. The prevalence of the HDV-1 genotype is high in Vietnam. No correlation was observed between HDV-HBV coinfections and disease progression when compared to HBV monoinfections. [ABSTRACT FROM AUTHOR]

Background Hepatitis E virus (HEV) infection can occur through consumption of undercooked pork meat or exposure to animal feces. Because there are scarce data only in developing countries, we assessed whether pigs might be a potential source of human HEV infections in Vietnam. In addition, we determined anti-HEV seroprevalences in the general population and in individuals professionally exposed to pigs and pork meat. Methods The study took place in Hanoi, Vietnam. Liver tissues from domestic pigs (n = 210) and serum samples obtained from individuals occupationally exposed to pigs and pork meat (n = 283) and from unexposed healthy controls (n = 168) were screened for HEV-ribonucleic acid (RNA) by reverse-transcription polymerase chain reaction. The exposed group was divided into pork meat vendors (n = 81), pig farmers (n = 96), and slaughterers (n = 106). Serum samples were subjected to HEV immunoglobulin (Ig)G and IgM enzyme-linked immunosorbent assays. The HEV genotypes were assessed by direct sequencing, followed by phylogenetic analyses. Results Hepatitis E virus seroprevalence was higher among persons occupationally exposed to pigs/pork meat compared with unexposed individuals (anti-HEV IgM 11% vs 6%, P =.07; anti-HEV IgG 53% vs 31%, P <.0001). Positivity of anti-HEV IgG among slaughterhouse staff was 66%, followed by 51% in pig-farmers and 38% in pork meat vendors (P =.00073). A similar trend was observed for IgM positivity. Of the pig liver tissues, 26 of 210 (12.4%) were positive for HEV-RNA and assessed to be HEV genotype 3. Conclusions Hepatitis E virus circulates in domestic pigs in Hanoi and constitutes a permanent zoonotic disease risk. The high HEV seroprevalence among occupationally exposed individuals indicates an associated risk of HEV infection. [ABSTRACT FROM AUTHOR]

Epilepsy surgery is traditionally difficult to pursue in resource-limited countries but is nevertheless essential in the treatment of medication-refractory, surgically amenable epilepsy. With the help of international collaboration, a successful epilepsy program was started in Vietnam. This article comprises a retrospective chart review, combined with prospective longitudinal follow-up of 35 cases of unilateral drug-resistant epilepsy in the temporal lobe who underwent temporal lobectomy, in Viet Duc University Hospital from May 2018 to September 2022. The female/male ratio was 0.6:1, and focal seizures with impaired awareness accounted for 97.14% of patients. Of patients with focal awareness seizures, 51.41% were localized and detected by electroencephalography. Postoperatively, 80% of patients were seizure free (Engel I) at 1 year, and the remaining 20% had worthwhile seizure improvement (Engel II). Postoperative temporal lobe pathology was categorized as follows: mesial temporal sclerosis (48.57%), focal cortical dysplasia (25.71%), and low-grade neoplasms (25.71%). Of patients, 17.14% had postoperative complications (5 infections and 1 transient extremity paresis), and there were no deaths. Even in low-resource environments, effective and safe surgical care can be provided for drug-resistant epilepsy caused by temporal lobe disease. This study serves as a model of international collaboration and support for future hospitals in low-resource environments to replicate. [ABSTRACT FROM AUTHOR]

Objectives: Burkholderia dolosa is a clinically important opportunistic pathogen in inpatients. Here we characterised an extensively drug-resistant and hypervirulent B. dolosa isolate from a patient hospitalised for stroke., Methods: Resistance to 41 antibiotics was tested with the agar disc diffusion, minimum inhibitory concentration, or broth microdilution method. The complete genome was assembled using short-reads and long-reads and the hybrid de novo assembly method. Allelic profiles obtained by multilocus sequence typing were analysed using the PubMLST database. Antibiotic-resistance and virulence genes were predicted in silico using public databases and the 'baargin' workflow. B. dolosa N149 phylogenetic relationships with all available B. dolosa strains and Burkholderia cepacia complex strains were analysed using the pangenome obtained with Roary., Results: B. dolosa N149 displayed extensive resistance to 31 antibiotics and intermediate resistance to 4 antibiotics. The complete genome included three circular chromosomes (6 338 630 bp in total) and one plasmid (167 591 bp). Genotypic analysis revealed various gene clusters (acr, amr, amp, emr, ade, bla and tet) associated with resistance to 35 antibiotic classes. The major intrinsic resistance mechanisms were multidrug efflux pump alterations, inactivation and reduced permeability of targeted antibiotics. Moreover, 91 virulence genes (encoding proteins involved in adherence, formation of capsule, biofilm and colony, motility, phagocytosis inhibition, secretion systems, protease secretion, transmission and quorum sensing) were identified. B. dolosa N149 was assigned to a novel sequence type (ST2237) and formed a mono-phylogenetic clade separated from other B. dolosa strains., Conclusions: This study provided insights into the antimicrobial resistance and virulence mechanisms of B. dolosa., (Copyright © 2024 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

Four isolates of the opportunistic pathogen Elizabethkingia anophelis were identified for the first time in a Vietnamese hospital and underwent antimicrobial susceptibility testing and genomic characterization by whole-genome sequencing. Complete, fully circularized genome sequences were obtained for all four isolates. Average Nucleotide Identity analysis and single nucleotide polymorphism phylogenetic analysis on the core genome showed that three of the four isolates were genetically distinct, ruling out the hypothesis of a single strain emergence. Antibiotic susceptibility testing highlighted multi-resistant phenotypes against most antimicrobial families, including beta-lactams, carbapenems, aminoglycosides, quinolones, macrolides, amphenicols, rifamycins and glycopeptides. Additionally, in silico genomic analysis was used to correlate the phenotypic susceptibility to putative resistance determinants, including resistance genes, point mutations and multidrug efflux pumps. Nine different resistance genes were located inside a single resistance pocket predicted to be a putative Integrative and Conjugative Element (ICE). This novel ICE was shared by three isolates from two different lineages and displayed similarity with ICEs previously reported in various Elizabethkingia and Chryseobacterium species. The role of such ICEs in pathogenicity, genome plasticity and antimicrobial resistance gene spread within the Flavobacteriaceae family needs to be further elucidated., (© 2024. The Author(s).)

Background: Breast cancer is the most common malignancy and remains the first cause of death related to cancer among Vietnamese women, with an incidence of 21,555 cases in 2020. Most breast cancer patients present with invasive disease and relatively large tumor sizes. While oncoplastic surgery (OPS) are commonly applied in Western countries, data on Asian population remains relatively limited., Objective: This study aims to assess the outcomes of level-2 oncoplastic techniques in breast-conserving surgeries at the Vietnam National Cancer Hospital., Methods: From January 2017 to June 2021, a cohort of 257 breast cancer patients who underwent breast-conserving surgery with OPS techniques were examined. Surgical complications, cosmetic outcome, recurrence and survival rates were assessed., Results: The mean age was 47.6±9.4 years, most patients had breast cup sizes B and C. The mean tumor size upon pathological examination was 2.00 ± 0.74 cm. Only 7 cases required reoperation, resulting in a mastectomy rate of 1.17%. The overall complication rate was low at 11.46%, with 9 cases (3.56%) experiencing delayed complications. Cosmetic results were rated as "excellent" in 20.6% and "good" in 60.5%, with a statistically significant difference. The rates of local recurrence, regional recurrence, and distant metastasis at five years were 2.78%, 1.19%, and 2.36%, respectively., Conclusion: The level 2 oncoplastic techniques had low complication rates, favorable oncological outcomes, and cosmetically satisfying results., Competing Interests: There are no conflicts of interest., (© 2024 Hoang Anh Dung, Le Hong Quang, Le Van Quang, Bui Tien Cong.)

Objectives: To determine potential associations of the rs2296651 variant (c.800C>T, S267F) of NTCP with HBV and HBV plus concomitant HDV infection as well as with the progression of related liver diseases., Methods: The S267F variant was genotyped by DNA sequencing in 620 HBV-infected patients and 214 healthy controls (HCs). Among the patients, 450 individuals were tested for HDV by a nested PCR assay. Logistic regression was applied to examine the association., Results: The S267F variant was found more frequently among HCs (16%) compared to HBV-infected (6%) and HBV-HDV co-infected patients (3%) (HBV patients vs HC: OR=0.32, P=0.00002 and HDV patients vs. HC: OR=0.17, P=0.018). The frequency of S267F variant was inversely correlated with CHB, LC or HCC patients compared with HCs (OR=0.31, P=0.001; OR=0.32, P=0.013; OR=0.34, P=0.002, respectively). S267F variant was also associated with decreased risk of the development of advanced liver cirrhosis (LC) and hepatocellular carcinoma (HCC) (Child B and C vs. Child A, OR=0.26, adjusted P=0.016; BCLC B,C,D vs. BCLC A, OR=0.038, P=0.045, respectively). In addition, patients with the genotype CT had lower levels of AST, ALT, total and direct bilirubin as well as higher platelet counts, indicating an association with a more favorable clinical outcome., Conclusion: The NTCP S267F variant of the SLC10A1 gene exhibits protective effects against HBV and HDV infection and is associated with a reduced risk of developing to advanced stages of LC and HCC., (Copyright © 2019 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

Hepatitis D caused by the hepatitis delta virus (HDV) is a serious health problem in many regions of the world. A total of 546 HBV-infected patients were enrolled from 2013 to 2015 and classified clinically into the subgroups of chronic hepatitis B (CHB, n = 191), liver cirrhosis (LC, n = 147) and hepatocellular carcinoma (HCC, n = 208). The patients were screened for HDV-RNA by nested PCR assays. HDV genotypes were assessed by direct sequencing, followed by phylogenetic analysis. HDV-RNA was identified in 13% (71/546) of HBV-infected patients. The highest HDV prevalence was found in the LC group (19.7%), followed by the HCC (12%) and CHB (8.9%) groups (P = 0.017). HDV/HBV coinfections were significantly associated with a rather unfavourable clinical outcome, in particular with LC development compared to HBV monoinfection. Phylogenetic analyses indicated that the genotype HDV1 was, with a prevalence of 91%, by far the most common genotype in Vietnam, followed by HDV2 with 9%. Other HDV genotypes were not observed. In accordance with previous data obtained a decade ago, our results confirm a continuing high prevalence of HDV infection in hepatitis B patients in northern Vietnam with the HDV1 genotype still being the predominant genotype. HDV nucleic acid testing to minimize the associated risk should be considered.

Background: Hepatitis D virus (HDV) infection is considered to cause more severe hepatitis than hepatitis B virus (HBV) monoinfection. With more than 9.5 million HBV-infected people, Vietnam will face an enormous health burden. The prevalence of HDV in Vietnamese HBsAg-positive patients is speculative. Therefore, we assessed the prevalence of HDV in Vietnamese patients, determined the HDV-genotype distribution and compared the findings with the clinical outcome., Methods: 266 sera of well-characterized HBsAg-positive patients in Northern Vietnam were analysed for the presence of HDV using newly developed HDV-specific RT-PCRs. Sequencing and phylogenetic analysis were performed for HDV-genotyping., Results: The HDV-genome prevalence observed in the Vietnamese HBsAg-positive patients was high with 15.4% while patients with acute hepatitis showed 43.3%. Phylogenetic analysis demonstrated a predominance of HDV-genotype 1 clustering in an Asian clade while HDV-genotype 2 could be also detected. The serum aminotransferase levels (AST, ALT) as well as total and direct bilirubin were significantly elevated in HDV-positive individuals (p<0.05). HDV loads were mainly low (<300 to 4.108 HDV-copies/ml). Of note, higher HDV loads were mainly found in HBV-genotype mix samples in contrast to single HBV-infections. In HBV/HDV-coinfections, HBV loads were significantly higher in HBV-genotype C in comparison to HBV-genotype A samples (p<0.05)., Conclusion: HDV prevalence is high in Vietnamese individuals, especially in patients with acute hepatitis B. HDV replication activity showed a HBV-genotype dependency and could be associated with elevated liver parameters. Besides serological assays molecular tests are recommended for diagnosis of HDV. Finally, the high prevalence of HBV and HDV prompts the urgent need for HBV-vaccination coverage.

Cryptococcal disease most commonly occurs in patients with an underlying immune deficit, most commonly HIV infection, and is due to Cryptococcus neoformans var. grubii. Occasionally disease due to this variety occurs in apparently immunocompetent patients. The relationship between strains infecting immunosuppressed and immunocompetent patients is not clear. Amplified fragment length polymorphism (AFLP) analysis was used to characterize the relationship between strains infecting HIV-infected and uninfected patients. Isolates from 51 HIV-uninfected patients and 100 HIV-infected patients with cryptococcal meningitis were compared. C. neoformans var. grubii VNI was responsible for infections in 73% of HIV-uninfected and 100% of HIV-infected patients. AFLP analysis defined two distinct clusters, VNIγ and VNIδ. The majority (84%) of isolates from HIV-uninfected patients were VNIγ, compared with only 38% of isolates from HIV-infected patients (odds ratio, 8.30; 95% confidence interval [CI], 3.04 to 26.6; P < 0.0001). In HIV-uninfected patients, underlying disease was less frequent in those with VNIγ infections. Two clusters of C. neoformans var. grubii VN1 are responsible for the majority of cases of cryptococcal meningitis in Vietnam. The distribution of these clusters differs according to the immune status of the host.