Waning antibody levels after COVID-19 vaccination with mRNA Comirnaty and inactivated CoronaVac vaccines in blood donors,Hong Kong,April 2020 to October 2021

The mRNA vaccine Comirnaty and the inactivated vaccine CoronaVac are both available in Hong Kong’s COVID-19 vaccination programme. We observed waning antibody levels in 850 fully vaccinated (at least 14 days passed after second dose) blood donors using ELISA and surrogate virus neutralisation test. The Comirnaty-vaccinated group’s (n = 593) antibody levels remained over the ELISA and sVNT positive cut-offs within the first 6 months. The CoronaVac-vaccinated group’s (n = 257) median antibody levels began to fall below the cut-offs 4 months after vaccination.     

Tuberous sclerosis presenting as an intraventricular tumour

We report a case of tuberous sclerosis in an 8 year old girl presenting for the first time with features of raised intracranial pressure due to a large intraventricular tumour. Occurrence of these tumours in children with tuberous sclerosis justifies cranial computerised tomography as a screening procedure to detect these tumours early.     

Immune activation during cerebellar dysfunction following Plasmodium falciparum malaria.

Evidence for immune activation was investigated in 12 patients with a rare syndrome of self-limiting, delayed onset cerebellar dysfunction following an attack of falciparum malaria which occurred 18-26 d previously. Concentrations of tumour necrosis factor, interleukin 6 and interleukin 2 were all significantly higher in serum samples of patients during cerebellar ataxia than in recovery sera and in the sera of 8 patients who did not develop delayed cerebellar dysfunction following an attack of falciparum malaria. Cytokine concentrations in the cerebrospinal fluid were also significantly higher in ataxic patients than in controls. These findings suggest that immunological mechanisms may play a role in delayed cerebellar dysfunction following falciparum malaria.     

Maternal comprehension of two growth monitoring charts in Sri Lanka

OBJECTIVE: To investigate the maternal comprehension of two different growth charts and to identify the group of mothers with poor comprehension. DESIGN: An experimental prospective study. SETTING: A child welfare clinic at the De Soysa Hospital for Women, Colombo, Sri Lanka. SUBJECTS: 932 mothers were studied regarding their interpretation of the type of growth chart their infants had been allocated. A total of 413 mothers interpreted the 'road-to-health' chart and 519 mothers interpreted the revised chart. A validated scoring system was used to assess comprehension. The two groups of mothers were comparable. RESULTS: 62.4% (324) mothers who interpreted the revised chart had good comprehension. Only 20.6% (85) mothers had similar comprehension with the road-to-health chart. Education up to or beyond grade 8 in school significantly improved comprehension. CONCLUSION: The design of the growth chart has a powerful effect on maternal comprehension of growth patterns. Length of schooling rather than literacy alone is a marker of a comprehending mother. The policy implications of these findings are that governments and agencies may need to redesign parent held growth charts to achieve better comprehension by mothers.     

Hemagglutinin pseudotyped lentiviral particles: characterization of a new method for avian H5N1 influenza sero-diagnosis.

BACKGROUND: Highly pathogenic avian influenza (HPAI) H5N1 has spread globally in birds and infected over 270 humans with an apparently high mortality rate. Serologic studies to determine the extent of asymptomatic H5N1 infection in humans and other mammals and to investigate the immunogenicity of current H5N1 vaccine candidates have been hampered by the biosafety requirements needed for H5N1 micro-neutralization tests. OBJECTIVE: Development of a serodiagnostic tool for highly pathogenic influenza that reproduces H5N1 biology but can be used with less biohazard. STUDY DESIGN: We have generated and evaluated H5 hemagglutinin pseudotyped lentiviral particles encoding the luciferase reporter (H5pp). RESULTS: H5pp entry into target cells depends on alpha2-3 cell surface sialic acids and requires low pH for membrane fusion. H5pp infectivity is specifically neutralized by sera from patients and animals infected with H5N1 and correlates well with conventional microneutralization test. CONCLUSIONS: H5pp reproduce H5N1 influenza virus entry into target cells and potentially provides a high-throughput and safe method for sero-epidemiology.     

Evaluation of real-time reverse transcriptase PCR and real-time loop-mediated amplification assays for severe acute respiratory syndrome coronavirus detection

We compared the performance of a recently established real-time loop-mediated amplification (LAMP) assay with the one from a highly sensitive quantitative PCR assay. None of these assays produced false-positive results in this study. For samples isolated from patients within the first 3 days of disease onset, the detection rate of the quantitative PCR assay was higher (14 of 15 were positive) than the LAMP assay (9 of 15 were positive). By contrast, the detection rates of these assays toward specimens sampled from patients with more than 3 days of illness were similar (32 of 44 for PCR and 33 of 44 for LAMP were positive). The simpler operation of LAMP might be a possible solution for on-site diagnosis.