ABSTRACT
Assessing the duration of humoral and cellular immunity remains key to overcome the current SARS-CoV-2 pandemic, especially in understudied populations in least developed countries. Sixty-four Cambodian individuals with laboratory-confirmed infection with asymptomatic or mild/moderate clinical presentation were evaluated for humoral immune response to the viral spike protein and antibody effector functions during acute phase of infection and at 6-9 months follow-up. Antigen-specific B cells, CD4+ and CD8+ T cells were characterized, and T cells were interrogated for functionality at late convalescence. Anti-spike (S) antibody titers decreased over time, but effector functions mediated by S-specific antibodies remained stable. S- and nucleocapsid (N)-specific B cells could be detected in late convalescence in the activated memory B cell compartment and are mostly IgG+. CD4+ and CD8+ T cell immunity was maintained to S and membrane (M) protein. Asymptomatic infection resulted in decreased ADCC and frequency of SARS-CoV-2-specific CD4+ T cells at late convalescence. Whereas anti-S antibodies correlated with S-specific B cells, there was no correlation between T cell response and humoral immunity. Hence, all aspects of a protective immune response are maintained up to nine months after SARS-CoV-2 infection in the absence of re-infection. One sentence summaryFunctional immune memory to SARS-CoV-2, consisting of polyfunctional antibodies, memory B cells and memory T cells are maintained up to nine months in a South-East Asian cohort in the absence of re-infection.
ABSTRACT
In 2009, we conducted a case-control study to explore the routes of HCV transmission in people living with HIV/AIDS (PLHIV) in Cambodia. Cases were HCV/HIV co-infected patients (who tested RT-PCR positive for HCV-RNA or had confirmed presence of HCV antibodies) (n = 44). Controls were HIV mono-infected patients, with no HCV antibodies (n = 160). They were recruited among the PLHIV presenting at one national reference centre of HIV/AIDS. Multivariate analysis showed that factors associated with the co-infection were the age older than 50 years (OR 5.4, 95 % confidence interval (CI) 1.5-19.6), the exposure to multiple parenteral infusions before the year 2000 (OR 3.4, 95 % CI 1.5-7.6), to surgery (OR 2.6, 95 % CI 1.2-5.7) and to fibroscopy (OR 2.4, 95 % CI 1.0-5.7). These results show the need to implement HCV screening in PLHIV, to support the implementation of national infection control guidelines, and to reinforce public awareness on the risks linked to parenteral medications.
