Kiat Ruxrungtham

This Review initiates a wide-ranging discussion over 2023 by selecting and exploring core themes to be investigated more deeply in papers submitted to the Vaccines Special Issue on the “Future of Epidemic and Pandemic Vaccines to Serve Global Public Health Needs”. To tackle the SARS-CoV-2 pandemic, an acceleration of vaccine development across different technology platforms resulted in the emergency use authorization of multiple vaccines in less than a year. Despite this record speed, many limitations surfaced including unequal access to products and technologies, regulatory hurdles, restrictions on the flow of intellectual property needed to develop and manufacture vaccines, clinical trials challenges, development of vaccines that did not curtail or prevent transmission, unsustainable strategies for dealing with variants, and the distorted allocation of funding to favour dominant companies in affluent countries. Key to future epidemic and pandemic responses will be sustainable, global-public-health-driven vaccine development and manufacturing based on equitable access to platform technologies, decentralised and localised innovation, and multiple developers and manufacturers, especially in low- and middle-income countries (LMICs). There is talk of flexible, modular pandemic preparedness, of technology access pools based on non-exclusive global licensing agreements in exchange for fair compensation, of WHO-supported vaccine technology transfer hubs and spokes, and of the creation of vaccine prototypes ready for phase I/II trials, etc. However, all these concepts face extraordinary challenges shaped by current commercial incentives, the unwillingness of pharmaceutical companies and governments to share intellectual property and know-how, the precariousness of building capacity based solely on COVID-19 vaccines, the focus on large-scale manufacturing capacity rather than small-scale rapid-response innovation to stop outbreaks when and where they occur, and the inability of many resource-limited countries to afford next-generation vaccines for their national vaccine programmes. Once the current high subsidies are gone and interest has waned, sustaining vaccine innovation and manufacturing capability in interpandemic periods will require equitable access to vaccine innovation and manufacturing capabilities in all regions of the world based on many vaccines, not just “pandemic vaccines”. Public and philanthropic investments will need to leverage enforceable commitments to share vaccines and critical technology so that countries everywhere can establish and scale up vaccine development and manufacturing capability. This will only happen if we question all prior assumptions and learn the lessons offered by the current pandemic. We invite submissions to the special issue, which we hope will help guide the world towards a global vaccine research, development, and manufacturing ecosystem that better balances and integrates scientific, clinical trial, regulatory, and commercial interests and puts global public health needs first.

Previous investigations conducted on a liposomal formulation for a SARS-CoV-2 DNA vaccine manufactured using the thin-film layer rehydration method showed promising immunogenicity results in mice. The adaptation of the liposomal formulation to a scalable and reproducible method of manufacture is necessary to continue the investigation of this vaccine candidate. Microfluidics manufacture shows high potential in method translation. The physicochemical characterization of the blank liposomes produced by thin-film layer rehydration or microfluidics were shown to be comparable. However, a difference in lipid nanostructure in the bilayer resulted in a significant difference in the hydration of the thin-film liposomes, ultimately altering their complexation behavior. A study on the complexation of liposomes with the DNA vaccine at various N/P ratios showed different sizes and Zeta-potential values between the two formulations. This difference in the complexation behavior resulted in distinct immunogenicity profiles in mice. The thin-film layer rehydration-manufactured liposomes induced a significantly higher response compared to the microfluidics-manufactured samples. The nanostructural analysis of the two samples revealed the critical importance of understanding the differences between the two formulations that resulted in the different immunogenicity in mice.

This paper provides a comprehensive summary of evidence to explore and position the role of serology testing in the context of coronavirus disease 19 (COVID-19) immunization and policy response in the Asia-Pacific (APAC) region. The document builds on a review of academic literature and existing policies followed by a process of discussion, validation, and feedback by a group of six experts. Six countries and territories—Australia, Hong Kong, India, Indonesia, Thailand, and Taiwan—were sampled to highlight the differing contexts and scenarios in the region. The review includes an overview of (1) the impact of the COVID-19 pandemic, including the emergence of Variants of Concern (VOCs), especially Omicron, (2) the introduction of immunization, (3) the available testing options and potential use of serology testing, (4) the landscape of guidelines and recommendations for their use, and (5) the barriers and challenges to implementing serology testing as a tool to support COVID-19 immunization. Based on the findings, the co-authors propose a set of recommendations to resolve knowledge gaps, to include the use of serology testing as part of the policy response, and to ensure adequate means of implementation. This paper’s target audience includes members of the academic community, medical societies, health providers and practitioners, and decision-makers.

In view of addressing the global necessity of an effective vaccine in the SARS-CoV-2 pandemic, a plasmid DNA vaccine, expressing for the spike (S) protein and formulated in lipoplexes, was manufactured and tested for in vitro transfection and in vivo immunogenicity. Blank cationic liposomes of 130.9 ± 5.8 nm in size and with a zeta potential of +48 ± 12 mV were formulated using the thin-film layer rehydration method. Liposomes were complexed with pCMVkan-S at different N/P ratios. Ratios of 0.25:1 and 1:1 were selected according to their complex stability and controlled size compared to other ratios and tested in vitro for transfection studies and in vivo for immunogenicity. Both selected formulations showed enhanced neutralizing antibody responses compared to pCMVkan-S injected alone, as well as an increased T cell response. The titers observed were similar to those of intramuscular electroporation (IM-EP), which was set as an efficacy goal.

Despite dramatic increases in new drugs and regimens, a combination of two nucleoside/nucleotide reverse transcriptase inhibitors (NRTIs) remains the backbone of many regimens to treat HIV. This article summarizes the pharmacokinetic characteristics of approved NRTIs that are currently in the international treatment and prevention guidelines. Compared to other NRTIs, tenofovir alafenamide fumarate (TAF) is more advantageous in terms of potency and safety. It is therefore a preferred choice in combination with emtricitabine (FTC) in most HIV treatment guidelines. The efficacy of the two-drug combination of NRTI/Integrase strand-transfer inhibitor, i.e. lamivudine/dolutegravir has been approved as an option for initial therapy. This regimen however has some limitations in patients with HBV coinfection. The two NRTI combinations tenofovir disproxil fumarate (TDF)/FTC and TAF/FTC have also been approved for pre-exposure prophylaxis (PrEP). Interestingly, a promising long-acting nucleoside reverse transcriptase translocation inhibitor, islatravir, formulated for implant was well tolerated and remained effective for up to a year, suggesting its potential as a single agent for PrEP. In the next decade, it remains to be seen whether NRTI-based regimens will remain the backbone of preferred ART regimens, or if the treatment will eventually move toward NRTI-sparing regimens to avoid long-term NRTI-toxicity.

Background: Long-term success of cART is possible if the regimen is convenient and less-toxic. This study assessed the efficacy and safety of switching from a first-line NNRTI or boosted PI-based regimens to RPV-based regimens among virologically suppressed participants in resource-limited setting (RLS). Methods: This is a prospective cohort study. Participants with plasma HIV-RNA < 50 copies/mL receiving cART were switched from a PI- or NNRTI-based, to a RPV-based regimen between January 2011 and April 2018. The primary endpoint was the proportion of patients with plasma HIV-1 RNA level < 50 copies/mL after 12 months of RPV. The secondary endpoint was the virological response at 24 months and safety endpoint (change in lipid profiles and kidney function from baseline to 12 months). Results: A total of 320 participants were enrolled into the study. The rationale for switching to RPV was based on toxicity of the current regimen (57%) or desire to simplify cART (41%). Totally, 177 (55%) and 143 (45%) participants were on NNRTI and boosted PI, respectively, prior to switching to RPV. After 12 months, 298 (93%) participants maintained virological suppression. There were significant improvements in the lipid parameters: TC (− 21 (IQR − 47 to 1) mg/dL; p < 0.001), LDL (− 14 (IQR − 37 to 11) mg/dL; p < 0.001) and TG (− 22 (IQR − 74 to 10) mg/dL; p < 0.001). Also, there was a small but statistically significant decrease in eGFR (− 4.3 (IQR − 12 to 1.1) mL/min per 1.73m2; p < 0.001). Conclusions: In RLS where integrase inhibitors are not affordable, RPV-based regimens are a good alternative option for PLHIV who cannot tolerate first-line NNRTI or boosted PI regimen, without prior NNRTI/PI resistance. Trial registration HIV-NAT 006 cohort, clinical trial number: NCT00411983

Background: Immune restoration is often incomplete after ART in HIV patients, both quantitatively and qualitatively. We studied the incidence and probability of CD4/CD8 normalization in an adult Thai HIV cohort and explored the predictive value of the ratio for developing of non-AIDS defining events (NAEs).Methods: We analyzed data from HIV-infected Thai adults between 1996 and 2017 in the HIV-NAT 006 prospective long-term cohort in Bangkok, Thailand. Normalization was defined as CD4/CD8 ratio ≥ 1 on two consecutive visits, and normalization probability was calculated using the Kaplan–Meier method. NAEs were a composite endpoint including cardiovascular or cerebrovascular diseases, chronic kidney diseases, non-AIDS defining malignancies and death. Multivariate Cox regression was used to evaluate demographic, disease and treatment characteristics associated with CD4/CD8 ratio normalization and NAEs.Results: A total of 800 ART-naïve patients with baseline CD4/CD8 ratio of < 0.8 who started combination ART, and had sustained virological suppression were enrolled. Participants were on ART for a median of 8.9 years and virologically suppressed for 6.1 years. The probabilities of CD4/CD8 normalization at 2, 5 and 10 years after virological suppression were 5.1%, 18.6% and 39.1%, respectively. Factors associated with normalization in multivariate analysis were female sex (hazard ratio [HR]: 2.47, 95% CI 1.71–3.56, p < 0.001) and baseline CD4 counts ≥ 350 cells/mm³(HR: 3.62, 95% CI 2.36–5.55), p < 0.001) vs. < 200 cells/mm³as reference. The second analysis explored the predictive value of CD4/CD8 ratio for NAEs. Older age (HR: 1.09, 95% CI 1.05–1.13, p < 0.01) and current CD4/CD8 ratio < 0.3 (HR: 3.02, 95% CI 1.27–7.21, p = 0.01) or between 0.3 and 0.45 (HR: 2.03, 95% CI 1.03–3.98, p = 0.04) vs. > 0.45 were independently associated with higher risk of progression to NAEs in the multivariate analysis.Conclusions: Our findings showed that complete immune recovery is uncommon in an Asian setting and earlier ART initiation at higher CD4 counts may have increased the ratio sooner. The findings demonstrate the use of CD4/CD8 ratio as a prognostic marker for clinical progression of NAEs.Trial registrationHIV-NAT 006 cohort, clinical trial number: NCT00411983

Ensuring that medicines meet quality standards is mandatory for ensuring safety and efficacy. There have been occasional reports of substandard generic medicines, especially in resource-limiting settings where policies to control quality may be less rigorous. As HIV treatment in Thailand depends mostly on affordable generic antiretrovirals (ARV), we performed quality assurance testing of several generic ARV available from different sources in Thailand and a source from Vietnam. We sampled Tenofovir 300mg, Efavirenz 600mg and Lopinavir/ritonavir 200/50mg from 10 primary hospitals randomly selected from those participating in the National AIDS Program, 2 non-government organization ARV clinics, and 3 private drug stores. Quality of ARV was analyzed by blinded investigators at the Faculty of Pharmaceutical Science, Chulalongkorn University. The analysis included an identification test for drug molecules, a chemical composition assay to quantitate the active ingredients, a uniformity of mass test and a dissolution test to assess in-vitro drug release. Comparisons were made against the standards described in the WHO international pharmacopeia. A total of 42 batches of ARV from 15 sources were sampled from January–March 2015. Among those generics, 23, 17, 1, and 1 were Thai-made, Indian-made, Vietnamese-made and Chinese-made, respectively. All sampled products, regardless of manufacturers or sources, met the International Pharmacopeia standards for composition assay, mass uniformity and dissolution. Although local regulations restrict ARV supply to hospitals and clinics, samples of ARV could be bought from private drug stores even without formal prescription. Sampled generic ARVs distributed within Thailand and 1 Vietnamese pharmacy showed consistent quality. However some products were illegally supplied without prescription, highlighting the importance of dispensing ARV for treatment or prevention in facilities where continuity along the HIV treatment and care cascade is available.

Recent evidence from HIV vaccine trials in humans and non-human primates suggests that nonneutralizing antibody functions, such as antibody-dependent cellular cytotoxicity (ADCC), are an important component of vaccine-mediated protection. Whether anti-HIV ADCC antibodies are present in seminal fluid, however, is not known. We assessed whether anti-HIV antibodies within seminal plasma mediate ADCC and activate natural killer (NK) cells. Using matched blood and seminal plasma samples, we detected anti-HIV IgG within samples from all 11 HIV-infected donors. Furthermore, anti-HIV antibodies within the seminal plasma triggered detectable ADCC in 9 of 11 donors and activated NK cells in 6 of 11 donors. The ability of seminal plasma-derived IgG to activate NK cells in an anti-HIV antibody-dependent manner was enhanced when IgG were enriched and other seminal plasma components were removed. These observations have relevance for understanding natural immunity to HIV infection and provide assistance with HIV vaccine design.

New evidence has emerged regarding when to commence antiretroviral therapy (ART), optimal treatment regimens, management of HIV co-infection with opportunistic infections, and management of ART failure. The 2014 guidelines were developed by the collaborations of the Department of Disease Control, Ministry of Public Health (MOPH) and the Thai AIDS Society (TAS). One of the major changes in the guidelines included recommending to initiating ART irrespective of CD4 cell count. However, it is with an emphasis that commencing HAART at CD4 cell count above 500 cell/mm3 is for public health, in term of preventing HIV transmission and personal benefit. In tuberculosis co-infected patients with CD4 cell counts ≤50 cells/mm3 or with CD4 cell counts >50 cells/mm3 who have severe clinical disease, ART should be initiated within 2 weeks of starting tuberculosis treatment. The preferred initial ART regimen in treatment naïve patients is efavirenz combined with tenofovir and emtricitabine or lamivudine. Plasma HIV viral load assessment should be done twice a year until achieving undetectable results; and will then be monitored once a year. CD4 cell count should be monitored every 6 months until CD4 cell count ≥350 cells/mm3 and with plasma HIV viral load 1,000 copies/mL while on ART. Ritonavir-boosted lopinavir or atazanavir in combination with optimized two nucleoside-analogue reverse transcriptase inhibitors is recommended after initial ART regimen failure. Long-term ART-related safety monitoring has also been included in the guidelines.