mRNA- and Adenovirus-Based Vaccines against SARS-CoV-2 in HIV-Positive People

Building a Better Silver Bullet: Current Status and Perspectives of Non-Viral Vectors for mRNA Vaccines

In recent years, messenger RNA (mRNA) vaccines have exhibited great potential to replace conventional vaccines owing to their low risk of insertional mutagenesis, safety and efficacy, rapid and scalable production, and low-cost manufacturing. With the great achievements of chemical modification and sequence optimization methods of mRNA, the key to the success of mRNA vaccines is strictly dependent on safe and efficient gene vectors. Among various delivery platforms, non-viral mRNA vectors could represent perfect choices for future clinical translation regarding their safety, sufficient packaging capability, low immunogenicity, and versatility. In this review, the recent progress in the development of non-viral mRNA vectors is focused on. Various organic vectors including lipid nanoparticles (LNPs), polymers, peptides, and exosomes for efficient mRNA delivery are presented and summarized. Furthermore, the latest advances in clinical trials of mRNA vaccines are described. Finally, the current challenges and future possibilities for the clinical translation of these promising mRNA vectors are also discussed.

Applications of SARS-CoV-2 serological testing: impact of test performance, sample matrices, and patient characteristics

Laboratory testing has been a key tool in managing the SARS-CoV-2 global pandemic. While rapid antigen and PCR testing has proven useful for diagnosing acute SARS-CoV-2 infections, additional testing methods are required to understand the long-term impact of SARS-CoV-2 infections on immune response. Serological testing, a well-documented laboratory practice, measures the presence of antibodies in a sample to uncover information about host immunity. Although proposed applications of serological testing for clinical use have previously been limited, current research into SARS-CoV-2 has shown growing utility for serological methods in these settings. To name a few, serological testing has been used to identify patients with past infections and long-term active disease and to monitor vaccine efficacy. Test utility and result interpretation, however, are often complicated by factors that include poor test sensitivity early in infection, lack of immune response in some individuals, overlying infection and vaccination responses, lack of standardization of antibody titers/levels between instruments, unknown titers that confer immune protection, and large between-individual biological variation following infection or vaccination. Thus, the three major components of this review will examine (1) factors that affect serological test utility: test performance, testing matrices, seroprevalence concerns and viral variants, (2) patient factors that affect serological response: timing of sampling, age, sex, body mass index, immunosuppression and vaccination, and (3) informative applications of serological testing: identifying past infection, immune surveillance to guide health practices, and examination of protective immunity. SARS-CoV-2 serological testing should be beneficial for clinical care if it is implemented appropriately. However, as with other laboratory developed tests, use of SARS-CoV-2 serology as a testing modality warrants careful consideration of testing limitations and evaluation of its clinical utility.

COVID-19 vaccination in people living with HIV and AIDS (PLWHA) in China: A cross-sectional study

COVID-19 appears to put people living with HIV and AIDS (PLWHA) at a higher risk of catastrophic consequences and mortality. However, investigations on the hesitancy and vaccination behavior of PLWHA in China were lacking compared to the general population. From January 2022 to March 2022, we conducted a multi-center cross-sectional survey of PLWHA in China. Logistic regression models were used to examine factors associated to vaccine hesitancy and COVID-19 vaccine uptake. Among 1424 participants, 108 participants (7.6%) were hesitant to be vaccinated while 1258 (88.3%) had already received at least one dose of the COVID-19 vaccine. Higher COVID-19 vaccine hesitancy was associated with older age, a lower academic level, chronic disease, lower CD4+ T cell counts, severe anxiety and despair, and high perception of illness. Lower education level, lower CD4+ T cell counts, and significant anxiety and depression were all associated with a lower vaccination rate. When compared to vaccinated participants, those who were not hesitant but nevertheless unvaccinated had a higher presence of chronic disease and lower CD4+ T cell count. Tailored interventions (e.g. targeted education programs) based on these linked characteristics were required to alleviate concerns for PLWHA in promoting COVID-19 vaccination rates, particularly for PLWHA with lower education levels, lower CD4+ T cell counts, and severe anxiety and depression.

The Use of Viral Vectors for Gene Therapy and Vaccination in Tuberculosis

Tuberculosis (TB), an infection caused by Mycobacterium tuberculosis (Mtb), is one of the primary causes of death globally. The treatment of TB is long and based on several drugs, producing problems in compliance and toxicity, increasing Mtb resistance to first-line antibiotics that result in multidrug-resistant TB and extensively drug-resistant TB. Thus, the need for new anti-TB treatments has increased. Here, we review some model strategies to study gene therapy based on the administration of a recombinant adenovirus that encodes diverse cytokines, such as IFNγ, IL12, GM/CSF, OPN, TNFα, and antimicrobial peptides to enhance the protective immune response against Mtb. These models include a model of progressive pulmonary TB, a model of chronic infection similar to latent TB, and a murine model of pulmonary Mtb transmission to close contacts. We also review new vaccines that deliver Mtb antigens via particle- or virus-based vectors and trigger protective immune responses. The results obtained in this type of research suggest that this is an alternative therapy that has the potential to treat active TB as an adjuvant to conventional antibiotics and a promising preventive treatment for latent TB reactivation and Mtb transmission. Moreover, Ad vector vaccines are adequate for preventing infectious diseases, including TB.

Inactivated SARS-CoV-2 vaccine candidate immunization on non-human primate animal model: B-cell and T-cell responses immune evaluation

Background

SARS-CoV-2 vaccine was proven to be an effective and efficient measure for mitigating pandemic. COVID-19 infection and mortality subsided along with the increaseing COVID-19 vaccination coverage. Vaccine and health resource equity are predominant factors in COVID-19 pandemic management. Vaccine development for Indonesia, aims to ensure a sustainable pandemic control and steady national stability restoration. A decent vaccine must induce immunity against COVID-19 with minimum adverse reaction. Immunogenicity and ability to induce neutralizing antibody evaluation needs to be performed as part of the SARS-CoV-2 inactivated vaccine development from East Java, Indonesia isolate (Vaksin Merah Putih-INAVAC).

Objective

This research demonstrated INAVAC performance in inducing the production neutralizing antibody along with its effects on CD4+ and CD8+ cells response in Macaca fascicularis (non-human primate).

Methods

Two dosages of 3 μg and 5 μg were tested, compared to sham (NaCl 0.9%) in 10 Macaca fascicularis (2 injection intramuscular with 14 days interval). All animals were monitored daily for clinical signs. Nasopharyngeal samples were analyzed using qRT-PCR while the serum were tested using ELISA and neutralization assay, whereas PBMCs were flowcytrometrically analyzed to measure CD4+ and CD8+ population.

Results

It is observed that both vaccine doses could stimulate relatively similar immune response and neutralizing antibody (end GMT post challenge = 905,1), whereas higher CD8+ cells response were reported in the 5 μg group after the 3rd day post-challenge. The dose of vaccine that produce adequate immune cell stimulation with neutralizing antibody induction can be adopted to clinical study, as favorable result of these parameters could predict minimum adverse reaction from inflammation response with balanced immune response.

Conclusions

Therefore, it is concluded that Vaksin Merah Putih-INAVAC with 3 μg dose showed a favorable potential to be developed and tested as human vaccine.

Effectiveness and Safety of SARS-CoV-2 Vaccination in HIV-Infected Patients-Real-World Study

The development of COVID-19 vaccines has been a triumph of biomedical research. However, there are still challenges, including assessment of their immunogenicity in high-risk populations, including PLWH. In the present study, we enrolled 121 PLWH aged >18 years, that were vaccinated against COVID-19 in the Polish National Vaccination Program. Patients filled in questionnaires regarding the side effects of vaccination. Epidemiological, clinical, and laboratory data were collected. The efficacy of COVID-19 vaccines was evaluated with an ELISA that detects IgG antibodies using a recombinant S1 viral protein antigen. The interferon-gamma release assay (IGRA) was applied to quantitate interferon-gamma (IFN-γ) to assess cellular immunity to SARS-CoV-2. In total, 87 patients (71.9%) received mRNA vaccines (BNT162b2-76 (59.5%), mRNA-1273- 11 (9.1%)). A total of 34 patients (28.09%) were vaccinated with vector-based vaccines (ChAdOx Vaxzevria- 20 (16.52%), Ad26.COV2.S- 14 (11.6%)). A total of 95 (78.5%) of all vaccinated patients developed a protective level of IgG antibodies. Only eight PLWH (6.6%) did not develop cellular immune response. There were six patients (4.95%) that did not develop a cellular and humoral response. Analysis of variance proved that the best humoral and cellular response related to the administration of the mRNA-1273 vaccine. COVID-19 vaccines were found to be immunogenic and safe in PLWH. Vaccination with mRNA vaccines were related to better humoral and cellular responses.

Persons with HIV Develop Spike-Specific Lymph Node Germinal Center Responses following SARS-CoV-2 Vaccination

COVID-19 disproportionately affects persons with HIV (PWH) in worldwide locations with limited access to SARS-CoV-2 vaccines. PWH exhibit impaired immune responses to some, but not all, vaccines. Lymph node (LN) biopsies from PWH demonstrate abnormal LN structure, including dysregulated germinal center (GC) architecture. It is not clear whether LN dysregulation prevents PWH from mounting Ag-specific GC responses in the draining LN following vaccination. To address this issue, we longitudinally collected blood and draining LN fine needle aspiration samples before and after SARS-CoV-2 vaccination from a prospective, observational cohort of 11 PWH on antiretroviral therapy: 2 who received a two-dose mRNA vaccine series and 9 who received a single dose of the Ad26.COV2.S vaccine. Following vaccination, we observed spike-specific Abs, spike-specific B and T cells in the blood, and spike-specific GC B cell and T follicular helper cell responses in the LN of both mRNA vaccine recipients. We detected spike-specific Abs in the blood of all Ad26.COV2.S recipients, and one of six sampled Ad26.COV2.S recipients developed a detectable spike-specific GC B and T follicular helper cell response in the draining LN. Our data show that PWH can mount Ag-specific GC immune responses in the draining LN following SARS-CoV-2 vaccination. Due to the small and diverse nature of this cohort and the limited number of available controls, we are unable to elucidate all potential factors contributing to the infrequent vaccine-induced GC response observed in the Ad26.COV2.S recipients. Our preliminary findings suggest this is a necessary area of future research.

Antibody response to different COVID-19 vaccines among the migrant workers of Bangladesh

Background

Due to the ongoing COVID-19 pandemic, various host countries such as Singapore, imposed entry requirements for migrant workers including pre-departure COVID-19 seroconversion proof. To combat COVID-19 worldwide, several vaccines have acquired conditional approval. This study sought to assess antibody levels after immunization with different COVID-19 vaccines among the migrant workers of Bangladesh.

Methods

Venous blood samples were collected from migrant workers who were vaccinated with different COVID-19 vaccines (n=675). Antibodies to SARS-CoV-2 spike protein (S) and nucleocapsid protein (N) were determined using Roche Elecsys^® Anti-SARS-CoV-2 S and N immunoassay, respectively.

Results

All participants receiving COVID-19 vaccines showed antibodies to S-protein, while 91.36% were positive for N-specific antibodies. The highest anti-S antibody titers were found among the workers who completed booster doses (13327 U/mL), received mRNA vaccines Moderna/Spikevax (9459 U/mL) or Pfizer-BioNTech/Comirnaty (9181 U/mL), and reported SARS-CoV-2 infection in the last six months (8849 U/mL). The median anti-S antibody titers in the first month since the last vaccination was 8184 U/mL, which declined to 5094 U/mL at the end of six months. A strong correlation of anti-S antibodies was found with past SARS-CoV-2 infection (p < 0.001) and the type of vaccines received (p <0.001) in the workers.Conclusion: Bangladeshi migrant workers receiving booster doses of vaccine, vaccinated with mRNA vaccines, and having past SARS-CoV-2 infection, mounted higher antibody responses. However, antibody levels waned with time. These findings suggest a need for further booster doses, preferably with mRNA vaccines for migrant workers before reaching host countries.

HIV and SARS-CoV-2 Pathogenesis and Vaccine Development

Although both HIV and SARS-CoV-2 are associated with pandemics, they are transmitted differently [...]

Efficacy of COVID-19 Vaccination in People Living with HIV: A Public Health Fundamental Tool for the Protection of Patients and the Correct Management of Infection

HIV/AIDS is considered a risk factor for increased mortality due to COVID-19. For this reason, it is essential to include this population in vaccination campaigns. Studies found that antibodies are lower in HIV+ patients than in healthy individuals. The aim of this study was to assess the immune response in a cohort of people living with HIV/AIDS (PLWH) vaccinated with COVID-19 vaccination in order to evaluate the role played by the HIV infection in the efficacy of this vaccine. We carried out a cross-sectional study in the period April-September 2021, involving a cohort of PLWH and a cohort of HIV-uninfected people as the control group. The efficacy of vaccination was high in both groups despite a slight and not significant difference between them. However, important differences were found according to the intensity of the immune response. Specifically, while in the HIV+ group almost a quarter of people had a low response, it is important to remark that the control group had only a high or intermediate response after vaccination. Our results suggest the high efficacy of the mRNA COVID-19 vaccine in PLWH and the importance to vaccinate against COVID-19 in these patients in order to increase their protection.

Comparison of the Immune Responses to COVID-19 Vaccines in Bangladeshi Population

Background: The adaptive immune response is a crucial component of the protective immunity against SARS-CoV-2, generated after infection or vaccination. Methods: We studied antibody titers, neutralizing antibodies and cellular immune responses to four different COVID-19 vaccines, namely Pfizer-BioNTech, Moderna Spikevax, AstraZeneca and Sinopharm vaccines in the Bangladeshi population (n = 1780). Results: mRNA vaccines Moderna (14,655 ± 11.3) and Pfizer (13,772 ± 11.5) elicited significantly higher anti-Spike (S) antibody titers compared to the Adenovector vaccine AstraZeneca (2443 ± 12.8) and inactivated vaccine Sinopharm (1150 ± 11.2). SARS-CoV-2-specific neutralizing antibodies as well as IFN-γ-secreting lymphocytes were more abundant in Pfizer and Moderna vaccine recipients compared to AstraZeneca and Sinopharm vaccine recipients. Participants previously infected with SARS-CoV-2 exhibited higher post-vaccine immune responses (S-specific and neutralizing antibodies, IFN-γ-secreting cells) compared to uninfected participants. Memory B (B_MEM), total CD8⁺T, CD4⁺ central memory (CD4⁺_CM) and T-regulatory (T_REG) cells were more numerous in AstraZeneca vaccine recipients compared to other vaccine recipients. Plasmablasts, B-regulatory (B_REG) and CD4⁺ effector (CD4⁺_EFF) cells were more numerous in mRNA vaccine recipients. Conclusions: mRNA vaccines generated a higher antibody response, while a differential cellular response was observed for different vaccine types, suggesting that both cellular and humoral responses are important in immune monitoring of different types of vaccines.