A Recent SARS-CoV-2 Infection Enhances Antibody-Dependent Cellular Cytotoxicity against Several Omicron Subvariants following a Fourth mRNA Vaccine Dose

Since the beginning of the SARS-CoV-2 pandemic, several variants of concern (VOCs), such as the Alpha, Beta, Gamma, Delta and Omicron variants, have arisen and spread worldwide. Today, the predominant circulating subvariants are sublineages of the Omicron variant, which have more than 30 mutations in their Spike glycoprotein compared to the ancestral strain. The Omicron subvariants were significantly less recognized and neutralized by antibodies from vaccinated individuals. This resulted in a surge in the number of infections, and booster shots were recommended to improve responses against these variants. While most studies mainly measured the neutralizing activity against variants, we and others previously reported that Fc-effector functions, including antibody-dependent cellular cytotoxicity (ADCC), play an important role in humoral responses against SARS-CoV-2. In this study, we analyzed Spike recognition and ADCC activity against several Omicron subvariants by generating cell lines expressing different Omicron subvariant Spikes. We tested these responses in a cohort of donors, who were recently infected or not, before and after a fourth dose of mRNA vaccine. We showed that ADCC activity is less affected than neutralization by the antigenic shift of the tested Omicron subvariant Spikes. Moreover, we found that individuals with a history of recent infection have higher antibody binding and ADCC activity against all Omicron subvariants than people who were not recently infected. With an increase in the number of reinfections, this study helps better understand Fc-effector responses in the context of hybrid immunity.

Spike recognition and neutralization of SARS-CoV-2 Omicron subvariants elicited after the third dose of mRNA vaccine

Several severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Omicron subvariants have recently emerged, becoming the dominant circulating strains in many countries. These variants contain a large number of mutations in their spike glycoprotein, raising concerns about vaccine efficacy. In this study, we evaluate the ability of plasma from a cohort of individuals that received three doses of mRNA vaccine to recognize and neutralize these Omicron subvariant spikes. We observed that BA.4/5 and BQ.1.1 spikes are markedly less recognized and neutralized compared with the D614G and other Omicron subvariant spikes tested. Also, individuals who have been infected before or after vaccination present better humoral responses than SARS-CoV-2-naive vaccinated individuals, thus indicating that hybrid immunity generates better humoral responses against these subvariants.

The Fc-effector function of COVID-19 convalescent plasma contributes to SARS-CoV-2 treatment efficacy in mice

COVID-19 convalescent plasmas (CCPs) are chosen for plasma therapy based on neutralizing titers and anti-Spike immunoglobulin levels. However, CCP characteristics that promote SARS-CoV-2 control are complex and incompletely defined. Using an in vivo imaging approach, we demonstrate that CCPs with low neutralizing (ID50 ≤ 1:250), but moderate to high Fc-effector activity, in contrast to those with poor Fc function, delay mortality and/or improve survival of SARS-CoV-2-challenged K18-hACE2 mice. The impact of innate immune cells on CCP efficacy depended on their residual neutralizing activity. Fractionation of a selected CCP revealed that IgG and Ig(M + A) were required during therapy, but the IgG fraction alone sufficed during prophylaxis. Finally, despite reduced neutralization, ancestral SARS-CoV-2-elicited CCPs significantly delayed Delta and Beta-induced mortality suggesting that Fc-effector functions contribute to immunity against VOCs. Thus, Fc activity of CCPs provide a second line of defense when neutralization is compromised and can serve as an important criterion for CCP selection.

Molecular Characterization and Antimicrobial Resistance in Neisseria gonorrhoeae, Nunavut Region of Inuit Nunangat, Canada, 2018-2019

We assessed antimicrobial resistance (AMR) in Neisseria gonorrhoeae in Nunavut, Canada, using remnant gonorrhea nucleic acid amplification test-positive urine specimens. This study confirms the feasibility of conducting N. gonorrhoeae AMR surveillance and highlights the diversity of gonococcal sequence types and geographic variation of AMR patterns in the territory.

Mycobacterium tuberculosis resistance in pulmonary TB patients in Cameroon: a phenotypic susceptibility assay

OBJECTIVE

To determine the resistance of Mycobacterium tuberculosis to first- and second-line agents in adult pulmonary tuberculosis (TB) patients in Cameroon using a novel phenotypic assay.

SETTING

Samples were collected from TB patients at Bamenda Hospital in Bamenda, Cameroon.

DESIGN

Samples were collected consecutively from adult pulmonary TB patients over a 2-month period. TREK Sensititre(TM) MYCOTB panels were used to perform phenotypic drug susceptibility testing (DST). Susceptibility/resistance was determined by comparing minimum inhibitory concentrations to standard critical concentrations established for first- and second-line anti-tuberculosis drugs.

RESULTS

Of 103 sputum samples processed, growth on Löwenstein-Jensen media was confirmed in 78 samples, 65 of which were suitable for DST. Thirty-nine strains (60%) were susceptible to all first- and second-line drugs. Five strains (8%) were categorized as multidrug-resistant TB. Two strains (3%) were classified as pre-extensively drug-resistant TB. Of those isolates susceptible to first-line drugs, 20% were resistant to at least one second-line drug.

CONCLUSION

Antimicrobial resistance may be higher than assumed in TB strains in Cameroon, especially with regard to second-line drugs. There remains a need for rapid, comprehensive DST.

Postoperative pain assessment in the neonatal intensive care unit

OBJECTIVES

To compare the convergent validity of two measures of pain (premature infant pain profile (PIPP) and crying, requires oxygen, increased vital signs, expression, and sleepless (CRIES)) in real life postoperative pain assessment in infants.

METHODS

This study was a prospective, repeated measures, correlational design. Two staff nurses were randomly assigned either the PIPP or CRIES measure. An expert rater assessed each infant after surgery, and once a day using the visual analogue scale (VAS).

SETTING

A level III neonatal intensive care unit in a metropolitan university affiliated paediatric hospital.

RESULTS

Pain was assessed in 51 neonates (28-42 weeks of gestational age) after surgery. There was no significant difference in the rates of change between the pain assessment measures across time using repeated measures analysis of variance (F(50,2) = 0.62, p = 0.540), indicating correlation between the measures. Convergent validity analysis using intraclass correlation showed correlation, most evident in the first 24 hours (immediately, 4, 8, 20, and 24 hours after the operation). Correlations were more divergent at 40 and 72 hours after surgery. No significant interactions were found between gestational age and measure (F(304,4) = 0.75, p = 0.563) and surgical group and measure (F(304,2) = 0.39, p = 0.680).

CONCLUSIONS

PIPP and CRIES are valid measures that correlate with pain for the first 72 hours after surgery in term and preterm infants. Both measures would provide healthcare professionals with an objective measure of a neonatal patient's pain.

Validation of the premature infant pain profile in the clinical setting

OBJECTIVE

The Premature Infant Pain Profile (PIPP) is a 7-indicator composite measure developed to assess acute pain in preterm and term neonates. It has been validated in studies using synchronized videotaping of infants undergoing procedures. The purpose of this study was to establish (a) construct validity of the PIPP and (b) inter- and intrarater reliability of the PIPP prospectively in the clinical environment.

DESIGN

A randomized, crossover design was used.

SETTING

The study was conducted in a Level III outborn neonatal intensive care unit.

PARTICIPANTS

A convenience sample of 43 neonates, stratified by gestational age, was studied.

INTERVENTIONS

Each infant experienced three separate, randomly ordered events: baseline, a painful event, and a nonpain event. Infants were videotaped and scored at the bedside using the PIPP by the nurse caring for the infant and the clinical nurse specialist who bad expertise in infant pain. The videotapes were later reviewed by two additional experts; one in real time and one using a second-to-second stop frame technique.

RESULTS

Repeated-measures analysis of the main effects and interactions yielded a statistically significant main effect for event (pain, nonpain, baseline), thus differentiating pain from nonpain and baseline events (F = 48, p = 0.0001) and establishing construct validity. Interrater reliability analysis of individual event scores of the PIPP yielded reliability coefficients of 0.93-0.96. Intrarater reliability coefficients analysis for individual events were equally high at 0.94-0.98.

CONCLUSIONS

This study demonstrates that the PIPP is a pain measure with good construct validity and excellent inter- and intrarater reliability for the assessment of procedural pain of preterm and term infants in clinical settings.