To Örebro University

Aim: Countries with varicella immunisation programmes have seen major reductions in disease burden. While two-dose schedules are now universally adopted, dosing ages vary, and some countries initially include catch-up vaccination of older children to speed impact. This modelling study assessed three two-dose schedules in the Swedish setting (1) 12 and 18 months, (2) 18 months and 5 years, and (3) 18 months and 7 years, with and without catch-up of susceptible children based on their medical history.

Methods: A deterministic, compartmental, age-structured, dynamic transmission model was used to evaluate the different strategies.

Results: With coverage similar to other childhood vaccinations in Sweden (>= 95%) but no catch-up, varicella cases are projected to decrease significantly within four years of programme start for all schedules modelled. However, a temporary rebound may occur around years 4-7 due to accumulating susceptibles before subsiding. Adding catch-up vaccination in this high-coverage setting accelerates and sustains the decline, with varicella disease burden significantly reduced within 2-3 years.

Conclusion: A national childhood varicella programme in Sweden could cut transmission and disease burden within 4 years, with catch-up vaccination speeding this to a few years and lowering rebound risk. The schedule should be guided by programmatic considerations.

AIM: This pilot study explored signs of immunological cross-reactivity between SARS-CoV-2 and human coronaviruses (HCoVs) in a Swedish school setting.

METHODS: A cross-sectional, hypothesis-generating study was conducted late 2020 before vaccines against COVID-19 were available. Forty-seven 7-8-year-old children, seventy-five 14-year-old adolescents, fifty-four 17-year-old adolescents, and 52 adult school staff were included, and immune responses to SARS-CoV-2 and HCoVs were assessed.

RESULTS: The SARS-CoV-2 seroprevalence was high in the older age groups (33%-41%). Seropositive individuals had significantly higher levels of antibodies against betacorona virus compared to seronegative individuals. SARS-CoV-2 seropositivity was rare among the 7-8-year-old children despite the high endemic context. SARS-CoV-2-specific T-cell responses in the absence of SARS-CoV-2-specific antibodies were seen in all age groups.

CONCLUSION: The data support a role for cross-reactive immune responses induced by recent HCoV infections, with cross-reactive T-cell responses providing protection against COVID-19 in young children.

BACKGROUND: Mozambique is a high-prevalence country for HIV and early detection of new HIV infections is crucial for control of the epidemic. We aimed to evaluate the accuracy of the 4th-generation rapid diagnostic test (RDT) AlereTM HIV Combo in detecting acute and seroconverted HIV-infection, among sexually-active women attending three clinical health centers in Maputo, Mozambique.

METHODS: Women aged 14-55 years (n = 920) seeking care at the Mavalane Health Area, Maputo (February 2018-January 2019) were included, and blood specimens sampled. Sociodemographic and sexual behavior data were collected. Point-of-care HIV testing was performed using Alere DetermineTM HIV-1/2 and Uni-GoldTM HIV-1/2. All samples were also tested using Enzygnost® HIV Integral 4 and Innotest® HIV Antigen mAb in laboratory. The 4th-generation RDT AlereTM HIV Combo was evaluated on serum samples in the laboratory. Finally, Innotest® HIV Antigen mAb, Enzygnost® HIV Integral 4 (Ag/Ab), and HIV RNA quantification acted as gold standard assays in the evaluation of AlereTM HIV Combo test for HIV antigen detection (in clinical samples and in three HIV-1 seroconversion panels).

RESULTS: The antibody component of the 4th generation AlereTM HIV Combo RDT demonstrated a sensitivity and specificity of 100% examining clinical samples. However, the test did not detect HIV p24 antigen in any clinical samples, while Innotest® HIV Antigen mAb, verified by Enzygnost® HIV Integral 4 (Ag/Ab) and/or HIV RNA quantification, detected HIV antigen in six clinical samples. Furthermore, the AlereTM HIV Combo RDT had a low sensitivity in the detection of HIV p24 antigen in seroconversion panels. The HIV prevalence among the examined women was 17.8%.

CONCLUSIONS: The 4th-generation RDT AlereTM HIV Combo showed similar sensitivity to the 3rd-generation RDTs to detect seroconverted HIV-infections. However, the sensitivity for detection of HIV p24 antigen and diagnosing acute HIV infections, before seroconversion, was low. There is an urgent need to develop and evaluate simple and affordable POC tests with high sensitivity and specificity for diagnosing individuals with acute HIV infection in resource-limited settings with high HIV prevalence.

BACKGROUND: Mucosal vaccines have the potential to induce protective immune responses at the sites of infection. Applying CRISPR/Cas9 editing, we aimed to develop a probiotic-based vaccine candidate expressing the HIV-1 envelope membrane-proximal external region (MPER) on the surface of E. coli Nissle 1917.

RESULTS: The HIV-1 MPER epitope was successfully introduced in the porin OmpF of the E. coli Nissle 1917 (EcN-MPER) and the modification was stable over 30 passages of the recombinant bacteria on the DNA and protein level. Furthermore, the introduced epitope was recognized by a human anti-HIV-1 gp41 (2F5) antibody using both live and heat-killed EcN-MPER, and this antigenicity was also retained over 30 passages. Whole-cell dot blot suggested a stronger binding of anti-HIV-1 gp41 (2F5) to heat-killed EcN-MPER than their live counterpart. An outer membrane vesicle (OMV) - rich extract from EcN-MPER culture supernatant was equally antigenic to anti-HIV-1 gp41 antibody which suggests that the MPER antigen could be harboured in EcN-MPER OMVs. Using quantitative ELISA, we determined the amount of MPER produced by the modified EcN to be 14.3 µg/108 cfu.

CONCLUSIONS: The CRISPR/Cas9 technology was an effective method for establishment of recombinant EcN-MPER bacteria that was stable over many passages. The developed EcN-MPER clone was devoid of extraneous plasmids and antibiotic resistance genes which eliminates the risk of plasmid transfer to animal hosts, should this clone be used as a vaccine. Also, the EcN-MPER clone was recognised by anti-HIV-1 gp41 (2F5) both as live and heat-killed bacteria making it suitable for pre-clinical evaluation. Expression of OmpF on bacterial surfaces and released OMVs identifies it as a compelling candidate for recombinant epitope modification, enabling surface epitope presentation on both bacteria and OMVs. By applying the methods described in this study, we present a potential platform for cost-effective and rational vaccine antigen expression and administration, offering promising prospects for further research in the field of vaccine development.

Sexually transmitted infections (STIs) have a profound impact on sexual and reproductive health worldwide. Syphilis, gonorrhea, chlamydia, and trichomoniasis are four currently curable STIs. However, most STI cases are asymptomatic and not detected without laboratory diagnostics. Hepatitis B virus, herpes simplex virus, human immunodeficiency virus (HIV), and human papillomavirus (HPV) are four viral and incurable infections, but they can be mitigated by treatment. We investigated the prevalence of selected sexually transmitted pathogens and their relationship with HPV and HIV infection in women from Maputo, the capital of Mozambique. A cross-sectional study was conducted on 233 non-pregnant women seeking health care relating to gynecological symptoms in Mavalane Health facilities in Maputo, between the 1st of February 2018 and the 30th of July 2019. Cervical brush samples were collected and DNA was extracted. Selected STIs including HPV were detected using multiplex STD and HPV Direct Flow Chip Kits through a manual Hybrispot platform (Vitro, Master Diagnostica, Sevilla, Spain). HIV testing was performed using rapid tests: Determine HIV 1/2 test (Alere Abbott Laboratories, Tokyo, Japan) for screening, and UniGold HIV (Trinity Biotech, Ireland) for confirmation. All women (n = 233) were negative for Haemophilus ducreyi and Herpes Simplex Virus-1 (HSV-1). Among the 233 women, a high prevalence of STIs was found (89%), 63% of the women were positive for HPV and 24% were HIV positive. Treponema pallidum (TP), Trichomonas vaginalis (TV), Herpes Simplex Virus-2 (HSV-2), and Chlamydia trachomatis (CT) were detected in 17%, 14%, 8%, and 8% of the women, respectively. As a common phenomenon, vaginal discharge (90%) was the lower genital tract symptom reported by the majority of the women. Co-infection with any STI and HPV was detected in 56% (130/233) while 45% (59/130) of the co-infections were with high-risk HPV (hrHPV) genotypes. Among the HPV-positive participants, infection by TP was the most prevalent (27%). In total, 28% (66/233) of the participants were positive for any hrHPV genotypes. Co-infection with any STI and HIV was found in 15% (34/233) of the study participants. There was a significant association between HPV infection and TP (p = 0.039) and HSV-2 (p = 0.005). TV, TP, and CT-S1-CT-S2 positivity were significantly more prevalent in HIV-positive participants. Pathobionts Ureaplasma urealyticum/parvum and Mycoplasma hominis were detected in 84.0% (195/233) and 45% (105/233), respectively. This present study describes a high prevalence of STIs. Co-infection between HPV and STIs was found in the majority of the study subjects. The high prevalence of HPV emphasizes the need for HPV vaccination to prevent cervical cancer in this population. Management of STIs is also important in women presenting with gynecological symptoms.

Major improvements have been made in the treatment and prevention of HIV/AIDS. However, a prophylactic vaccine is still unavailable, and several vaccine-candidate trials yielded less than favourable results. Given that the HIV pandemic has not slowed down significantly, there is an urgent need for the development of an effective vaccine. The HIV-1 Gag protein, a key player in HIV particle assembly, is a suitable antigen for use in HIV vaccine development since antibodies targeting HIV-1 Gag will interfere with the replication of the virus. In our vaccine development strategy, it was important for us to develop a candidate for mucosal administration. This is because the mucosal route is the major site for HIV transmission and early viral replication, which is associated with extensive and rapid depletion of CD4+ T-cells in the Gut-Associated Lymphoid Tissue (GALT). Here, we transformed probiotic strains of Lactobacillus plantarum and Lactobacillus fermentum with the recombinant plasmid vectors pSIP409 and pSIP411 harbouring the HIV-1 GagM gene. Following electroporation, HIV-1 GagM expression was induced in the probiotics using peptide pheromone. Via PCR and sequencing, the presence of GagM was confirmed in the L. plantarum+ pSIP409-GagM and L. fermentum+ pSIP411-GagM clones. Protein expression was induced with peptide pheromone. Then, protein expression was confirmed by western blotting with goat anti-HIV p24 primary antibody and anti-goat secondary antibody. ELISA was also performed to confirm the antigenicity of the HIV-1 Gag antigen and to also quantify the antigen in the two Lactobacilli clones. Our results show that 1.5×109 CFU of L. plantarum+ pSIP409-GagM expressed 125μg of HIV-1 Gag and 1.9×109 CFU of L. fermentum+ pSIP411-GagM clones expressed 125μg of HIV-1 Gag respectively. In vitro digestion with pepsin, pancreatin and bile salts suggested that partial digestion of the probiotic vaccine candidates may occur when administered orally. Taken together, our probiotic HIV-1 vaccine candidates showed good prospects for further immunological analysis via animal trial.

The mucosal surfaces throughout the body are constantly exposed to microorganisms. The mucosal surfaces accommodate a large part of the body’s immune system. For effective vaccination, it is believed that direct immunization on mucosal surfaces will be more effective than the more conventional systemic immunization. Certain probiotic bacteria provide significant adjuvant effects that may be utilized for the desired immune response. Virus-like particles (VLPs) are complexes of viral proteins that without being infectious are efficient in mimicking the natural viral structures. While presenting the patterns of viral antigens, the VLPs have been shown to efficiently interact with dendritic cells and be effective in triggering the B and T-cell immunity. HIV-1 Gag is one of the most highly conserved structural antigens and contains several immunodominant T- and B-cell epitopes. Mosaic Gag protein matches 74% of 9-amino-acid potential epitopes in global Gag sequences thus maximizing the coverage of potential T-cell epitopes for a viral population.The current study aimed to develop probiotic strains of Lactobacillus plantarum NC8 and E. coli Nissle 1917 that produced recombinant mosaic HIV-1 Gag protein as VLPs.For the transient expression of the mosaic HIV-1 Gag protein (GagM), the gene-carrying expression vectors were transformed into the L. plantarum and in probiotic E.coli Nissle 1917. Protein expression of the GagM was shown to lead to the formation of the VLPs of the recombinant HIV-1 Gag proteins. This was confirmed through immunoblotting and transmission electron microscopy (TEM).Our study shows that probiotic lactobacteria can be developed to express HIV-1 Gag VLPs, which may be used for VLP production and potentially for vaccine delivery. Further evaluation of the concept is merited.

Flaviviruses are a threat to public health and can cause major disease outbreaks. Tick-borne encephalitis (TBE) is caused by a flavivirus, and it is one of the most important causes of viral encephalitis in Europe and is on the rise in Sweden. As there is no antiviral treatment availa-ble, vaccination remains the best protective measure against TBE. Currently available TBE vaccines are based on formalin-inactivated virus produced in cell culture. These vaccines must be delivered by intramuscular injection, have a burdensome immunization schedule, and may exhibit vaccine failure in certain populations. This project aimed to develop an edible TBE vaccine to trigger a stronger immune response through oral delivery of viral antigens to mucosal surfaces. We demonstrated successful expression and post-translational processing of flavivirus structural pro-teins which then self-assembled to form virus-like particles in Nicotiana benthamiana. We performed oral toxicity tests in mice using various plant species as potential bioreactors and evaluated the immunogenicity of the resulting edible vaccine candidate. Mice immunized with the edible vaccine candidate did not survive challenge with TBE virus. Interestingly, immunization of female mice with a commercial TBE vaccine can protect their offspring against TBE virus infection. 

The detection of vaccine-induced HIV antibody responses by rapid diagnostic tests (RDTs) may confound the interpretation of HIV testing results. We assessed the impact of vaccine-induced seroreactivity (VISR) on the diagnosis of HIV in sub-Saharan Africa. Samples collected from healthy participants of HIVIS and TaMoVac HIV vaccine trials after the final vaccination were analyzed for VISR using HIV testing algorithms used in Mozambique and Tanzania that employ two sequential RDTs. The samples were also tested for VISR using Enzygnost HIV Integral 4 ELISA and HIV western blot assays. Antibody titers to subtype C gp140 were determined using an in-house enzyme-linked immunosorbent assay (ELISA). The frequency of VISR was 93.4% (128/137) by Enzygnost HIV Integral 4 ELISA, and 66.4% (91/137) by western blot assay (WHO interpretation). The proportion of vaccine recipients that would have been misdiagnosed as HIV-positive in Mozambique was half of that in Tanzania: 26.3% (36/137) and 54.0% (74/137), respectively, p < 0.0001. In conclusion, the HIV RDTs and algorithms assessed here will potentially misclassify a large proportion of the HIV vaccine recipients if no other test is used. Increased efforts are needed to develop differential serological or molecular tools for use at the point of care.

OBJECTIVES: The aim of this study was to determine the prevalence of infection, genotypes and risk factors for human papillomavirus (HPV) among men who have sex with men (MSM) and transgender women living with and without HIV in Pakistan. Anal infection with HPV is very common worldwide among MSM, particularly among MSM living with HIV. The high prevalence of HIV among MSM and male-to-female transgendered individuals in Pakistan is a significant health concern since access to screening and health-seeking is often delayed in this stigmatised key population.

DESIGN: This cross-sectional study was conducted between March 2016 and November 2017.

PARTICIPANTS, SETTING AND DATA COLLECTION: This study recruited MSM and transgender-women who self-reported to have had anal sex in the last 6 months, and were at least 18 years of age, from the sexual health and antiretroviral therapy centres. Structured questionnaires were administered, and blood samples were obtained to confirm HIV status. Anal swabs were collected for HPV-DNA detection and typing.

MAIN OUTCOME MEASURES: The primary outcome was the prevalence of 'HPV-DNA infection'. The prevalence ratios (PR) were calculated using Cox proportional hazard model algorithms to analyse the association between exposure variables and HPV-infection.

RESULTS: Complete data were available for 298 MSM and transgender women (HIV +n=131; HIV-n=167). The overall HPV-DNA prevalence was 65.1% and was higher in participants living with HIV as compared with HIV-negative (87% vs 48%; χ²p≤0.001). Likewise, 28.9% of participants living with HIV were infected with two or more than two types of HPV as compared with 18.8% participants without HIV(χ² p≤0.001). The most frequent HPV type was HPV6/11 (46.9%), followed by HPV16 (35.1%), HPV18 (23.2%) and HPV35 (21.1%). HIV status (PR 2.81, 95% CI 2.16 to 3.82) and never condom use (PR 3.08, 95% CI 1.69 to 5.60)) were independently associated with prevalence of 'anal-HPV16 infection' when adjusting for confounding for age, other sexual and behavioural factors, for example, smoking and alcohol consumption.

CONCLUSION: High prevalence of HPV indicates a substantial future risk of anal cancer in Pakistani MSM and transgender women, and particularly in those living with HIV. Current findings support anal Pap-smear HPV screening for this particular group and vaccination efforts for future generations.