Percorrer por autor "Yameen, Maliha"
A mostrar 1 - 3 de 3
Resultados por página
Opções de ordenação
- Comparative study of humoral and cellular immunity against SARS-CoV-2 induced by different COVID-19 vaccine types: insights into protection against wildtype, Delta and JN.1 omicron strainsPublication . Hasan, Zahra; Masood, Kiran Iqbal; Qaiser, Shama; Kanji, Akbar; Mwenda, Fridah; Alenquer, Marta; Iqbal, Junaid; Ferreira, Filipe; Wassan, Yaqub; Balouch, Sadaf; Yameen, Maliha; Hussain, Shahneel; Begum, Kehkashan; Feroz, Khalid; Muhammad, Sajid; Sadiqa, Ayesha; Akhtar, Mishgan; Habib, Atif; Ahmed, Syed Muhammad Areeb; Mian, Afsar Ali; Hussain, Rabia; Amorim, Maria Joao; Bhutta, Zulfiqar A.We investigated the effectiveness of different COVID-19 vaccinations administered in Pakistan by studying the effect of inactivated virus, mRNA and vector formulations. This study in 916 participants was conducted between October 2021 and July 2022. Subjects receiving inactivated (A), mRNA (B), one-dose vector (C), and two-dose vector (D) vaccines were sampled at baseline, 6, 12, and 24 weeks. Serum IgG antibodies to wildtype Spike and its receptor binding domain (RBD) were measured. Pseudovirus particle-based neutralizing assays against wildtype, Delta, and JN.1 variants were performed. T cell IFN-γ responses to SARS-CoV-2 antigens were measured. Participants were aged 37.05 ± 14.44 years and comprised 48.6 % females. Baseline Spike seropositivity rose from 90 % to 96 % by 24 weeks; and 40 % to 90 % against RBD. Group B participants had the highest anti-RBD levels which peaked by 6 weeks. IgG RBD in group A and C increased up until 24 weeks. Anti-RBD levels were reduced in those over 50 years. At baseline neutralizing titers were present at 38.5 % against wildtype and in 34.2 % against Delta variants. Titers doubled in vaccine groups A-C by 12 weeks, with highest titers in B and lowest in group C participants. At baseline, neutralizing titers against the JN.1 variant were absent but low titers were evident in 10 % of participants after 12 weeks. T cell reactivity to SARS-CoV-2 increased from 31 % at baseline to 50 % in group A and 73 % in group B participants by 6 weeks after vaccination. Presence of immunity against wildtype and Delta variants in one-third of participants at baseline could be due to sub-clinical infections. Increase in humoral and cellular immunity was greater after mRNA as compared with inactivated vaccinations. As COVID-19 morbidity in the population remained low, our data supports effectiveness of multiple vaccine formulations in protecting against severe COVID-19 in this high transmission population.
- Humoral and T cell responses to SARS-CoV-2 reveal insights into immunity during the early pandemic period in PakistanPublication . Masood, Kiran Iqbal; Qaiser, Shama; Abidi, Syed Hani; Khan, Erum; Mahmood, Syed Faisal; Hussain, Areeba; Ghous, Zara; Imtiaz, Khekahsan; Ali, Natasha; Hasan, Muhammad; Memon, Haris Ali; Yameen, Maliha; Ali, Shiza; Baloch, Sadaf; Lakhani, Gulzar; Alves, Paula M.; Iqbal, Najeeha Talat; Ahmed, Kumail; Iqbal, Junaid; Bhutta, Zulfiqar A.; Hussain, Rabia; Rottenberg, Martin; Simas, J. Pedro; Veldhoen, Marc; Ghias, Kulsoom; Hasan, ZahraBackground: Protection against SARS-CoV-2 is mediated by humoral and T cell responses. Pakistan faced relatively low morbidity and mortality from COVID-19 through the pandemic. To examine the role of prior immunity in the population, we studied IgG antibody response levels, virus neutralizing activity and T cell reactivity to Spike protein in a healthy control group (HG) as compared with COVID-19 cases and individuals from the pre-pandemic period (PP). Methods: HG and COVID-19 participants were recruited between October 2020 and May 2021. Pre-pandemic sera was collected before 2018. IgG antibodies against Spike and its Receptor Binding Domain (RBD) were determined by ELISA. Virus neutralization activity was determined using a PCR-based micro-neutralization assay. T cell – IFN-γ activation was assessed by ELISpot. Results: Overall, the magnitude of anti-Spike IgG antibody levels as well as seropositivity was greatest in COVID-19 cases (90%) as compared with HG (39.8%) and PP (12.2%). During the study period, Pakistan experienced three COVID-19 waves. We observed that IgG seropositivity to Spike in HG increased from 10.3 to 83.5% during the study, whilst seropositivity to RBD increased from 7.5 to 33.3%. IgG antibodies to Spike and RBD were correlated positively in all three study groups. Virus neutralizing activity was identified in sera of COVID-19, HG and PP. Spike reactive T cells were present in COVID-19, HG and PP groups. Individuals with reactive T cells included those with and without IgG antibodies to Spike. Conclusions: Antibody and T cell responses to Spike protein in individuals from the pre-pandemic period suggest prior immunity against SARS-CoV-2, most likely from cross-reactive responses. The rising seroprevalence observed in healthy individuals through the pandemic without known COVID-19 may be due to the activation of adaptive immunity from cross-reactive memory B and T cells. This may explain the more favourable COVID-19 outcomes observed in this population.
- Investigating the impact of prior COVID-19 on IgG antibody and interferon γ responses after BBIBP-CorV vaccination in a disease endemic population: a prospective observational studyPublication . Hasan, Zahra; Masood, Kiran Iqbal; Qaiser, Shama; Khan, Erum; Hussain, Areeba; Ghous, Zara; Khan, Unab; Yameen, Maliha; Hassan, Imran; Nasir, Muhammad Imran; Qazi, Muhammad Farrukh; Memon, Haris Ali; Ali, Shiza; Baloch, Sadaf; Bhutta, Zulfiqar A.; Veldhoen, Marc; Simas, J. Pedro; Mahmood, Syed Faisal; Ghias, Kulsoom; Hussain, RabiaBackground and Aims: COVID-19 vaccinations have reduced morbidity and mortality from the disease. Antibodies against severe acute respiratory syndrome coronavirus 2 (SARS‑CoV‑2) have been associated with immune protection. Seroprevalence studies revealed high immunoglobulin G (IgG) antibody levels to SARS-CoV-2 in the Pakistani population before vaccinations. We investigated the effect of BBIBP-CorV vaccination on circulating IgG antibodies and interferon (IFN)-γ from T cells measured in a cohort of healthy individuals, with respect to age, gender, and history of COVID-19. Methods: The study was conducted between April and October 2021. BBIBP-CorV vaccinated participants were followed up to 24 weeks. Antibodies to SARS-CoV-2 Spike protein and its receptor-binding domain (RBD) were measured. IFNγ secreted by whole blood stimulation of Spike protein and extended genome antigens was determined. Results: Study participants with a history of prior COVID-19 displayed a higher magnitude of IgG antibodies to Spike and RBD. IgG seropositivity was greater in those with prior COVID-19, aged 50 years or younger and in females. At 24 weeks after vaccination, 37.4% of participants showed IFN-γ responses to SARS-CoV-2 antigens. T cell IFN-γ release was higher in those with prior COVID-19 and those aged 50 years or less. Highest IFN-γ release was observed to extended genome antigens in individuals both with and without prior COVID-19. Conclusion: We found that IgG seropositivity to both Spike and RBD was affected by prior COVID-19, age and gender. Importantly, seropositive responses persisted up to 24 weeks after vaccination. Persistence of vaccine induced IgG antibodies may be linked to the high seroprevalence observed earlier in unvaccinated individuals. Increased T cell reactivity to Spike and extended genome antigens reflects cellular activation induced by BBIBP-CorV. COVID-19 vaccination may have longer lasting immune responses in populations with a higher seroprevalence. These data inform on vaccination booster policies for high-risk groups.