Safety and immunogenicity of booster vaccination and fractional dosing with Ad26.COV2.S or BNT162b2 in Ad26.COV2.S-vaccinated participants

We report the safety and immunogenicity of fractional and full dose Ad26.COV2.S and BNT162b2 in an open label phase 2 trial of participants previously vaccinated with a single dose of Ad26.COV2.S, with 91.4% showing evidence of previous SARS-CoV-2 infection. A total of 286 adults (with or without HIV) were enrolled >4 months after an Ad26.COV2.S prime and randomized 1:1:1:1 to receive either a full or half-dose booster of Ad26.COV2.S or BNT162b2 vaccine. B cell responses (binding, neutralization and antibody dependent cellular cytotoxicity-ADCC), and spike-specific T-cell responses were evaluated at baseline, 2, 12 and 24 weeks post-boost. Antibody and T-cell immunity targeting the Ad26 vector was also evaluated. No vaccine-associated serious adverse events were recorded. The full- and half-dose BNT162b2 boosted anti-SARS-CoV-2 binding antibody levels (3.9- and 4.5-fold, respectively) and neutralizing antibody levels (4.4- and 10-fold). Binding and neutralizing antibodies following half-dose Ad26.COV2.S were not significantly boosted. Full-dose Ad26.COV2.S did not boost binding antibodies but slightly enhanced neutralizing antibodies (2.1-fold). ADCC was marginally increased only after a full-dose BNT162b2. T-cell responses followed a similar pattern to neutralizing antibodies. Six months post-boost, antibody and T-cell responses had waned to baseline levels. While we detected strong anti-vector immunity, there was no correlation between anti-vector immunity in Ad26.COV2.S recipients and spike-specific neutralizing antibody or T-cell responses post-Ad26.COV2.S boosting. Overall, in the context of hybrid immunity, boosting with heterologous full- or half-dose BNT162b2 mRNA vaccine demonstrated superior immunogenicity 2 weeks post-vaccination compared to homologous Ad26.COV2.S, though rapid waning occurred by 12 weeks post-boost. Trial Registration: The study has been registered to the South African National Clinical Trial Registry (SANCTR): DOH-27-012022-7841. The approval letter from SANCTR has been provided in the up-loaded documents.

Obstetric and neonatal outcomes in South Africa

BACKGROUND

Background epidemiologic population data from low- and middle-income countries (LMIC), on maternal, foetal and neonatal adverse outcomes are limited. We aimed to estimate the incidence of maternal, foetal and neonatal adverse outcomes at South African maternal vaccine trial sites as reported directly in the clinical notes as well as using the 'Global Alignment of Immunization Safety Assessment in Pregnancy' case definitions (GAIA-CDs). GAIA-CDs were utilized as a tool to standardise data collection and outcome assessment, and the applicability and utility of the GAIA-CDs was evaluated in a LMIC observational study.

METHODS

We conducted a retrospective record review of maternity and neonatal case records for births that occurred in Soweto, Inner City- Johannesburg and Metro-East Cape Town, South Africa, between 1st July 2017 and 30th June 2018. Study staff abstracted data from randomly selected medical charts onto standardized study-specific forms. Incidence (per 100,000 population) was calculated for adverse maternal, foetal and neonatal outcomes, which were identified as priority outcomes in vaccine safety studies by the Brighton Collaboration and World Health Organization. Outcomes reported directly in the clinical notes and outcomes which fulfilled GAIA-CDs were compared. Incidence of outcomes was calculated by combining cases which were either reported in clinical notes by attending physicians and/ or fulfilled GAIA-CDs.

FINDINGS

Of 9371 pregnant women enrolled, 27·6% were HIV-infected, 19·9% attended antenatal clinic in the 1st trimester of pregnancy and 55·3% had ≥1 ultrasound examination. Fourteen percent of women had hypertensive disease of pregnancy, 1·3% had gestational diabetes mellitus and 16% experienced preterm labour. There were 150 stillbirths (1·6%), 26·8% of infants were preterm and five percent had microcephaly. Data available in clinical notes for some adverse outcomes, including maternal- & neonatal death, severe pre-eclampsia/ eclampsia, were able to fulfil GAIA-CDs criteria for all of the clinically-reported cases, however, missing data required to fulfil other GAIA-CD criteria (including stillbirth, gestational diabetes mellitus and gestational hypertension) led to poor correlation between clinically-reported adverse outcomes and outcomes fulfilling GAIA-CDs. Challenges were also encountered in accurately ascertaining gestational age.

INTERPRETATION

This study contributes to the expanding body of data on background rates of adverse maternal and foetal/ neonatal outcomes in LMICs. Utilization of GAIA-CDs assists with alignment of data, however, some GAIA-CDs require amendment to improve the applicability in LMICs.

FUNDING

This study was funded by Pfizer (Inc).

More Frequent HIV Viral Load Testing With Point-Of-Care Tests Detects Elevated Viral Load Earlier in Postpartum HIV-Positive Women in a Randomized Controlled Trial in Two Clinics in Johannesburg, South Africa

BACKGROUND

Elevated maternal HIV viral load (VL) increases vertical transmission risk for breastfeeding children. This randomized controlled trial in Johannesburg primarily evaluated whether 3-monthly point-of-care testing, with laboratory-based standard-of-care testing (arm 2), compared with 6-monthly laboratory-based VL testing (arm 1) in postpartum women living with HIV receiving first-line tenofovir-emtricitabine-efavirenz antiretroviral treatment improved VL suppression, factors associated with nonsuppression, and drug resistance in those with virologic failure.

METHODS

Mother-child pairs were enrolled July 2018-April 2019 at the child's 6/10/14-week clinic visit. Women were randomized 1:1 to arm 1 or 2. Trained staff performed point-of-care VL testing using the Cepheid's Xpert HIV-1 VL assay. We fitted a generalized linear mixed model with VL suppression (<50 copies/mL (cps/mL) and <1000 cps/mL) at enrollment and 6, 12, and 18 months postpartum as the outcome and indicator variables for time, study site, study arm, and interaction variables. The final model tested for a difference by study arm, pooling across time points.

RESULTS

Of 405 women enrolled (204 arm 1 and 201 arm 2), 249 (61%) remained in follow-up through 18 months. There was no difference in VL suppression between arms at 6, 12, or 18 months. VL suppression rate (<50 cps/mL) at 18 months was 64.8% in arm 1 and 63.0% in arm 2 (P = 0.27). On bivariate analysis, there was an association with late antenatal booking and being in arm 2 for nonsuppressed VL, but no significant association with breastfeeding. HIV drug resistance was found in 12 of 23 participants (52.2%).

CONCLUSION

We found no significant difference in VL suppression with more frequent VL testing in postpartum women living with HIV receiving first-line efavirenz-based antiretroviral treatment.

Safety and immunogenicity of booster vaccination and fractional dosing with Ad26.COV2.S or BNT162b2 in Ad26.COV2.S-vaccinated participants

Background

We report the safety and immunogenicity of fractional and full dose Ad26.COV2.S and BNT162b2 in an open label phase 2 trial of participants previously vaccinated with a single dose of Ad26.COV2.S, with 91.4% showing evidence of previous SARS-CoV-2 infection.

Methods

A total of 286 adults (with or without HIV) were enrolled >4 months after an Ad26.COV2.S prime and randomized 1:1:1:1 to receive either a full or half-dose booster of Ad26.COV2.S or BNT162b2 vaccine. B cell responses (binding, neutralization and antibody dependent cellular cytotoxicity-ADCC), and spike-specific T-cell responses were evaluated at baseline, 2, 12 and 24 weeks post-boost. Antibody and T-cell immunity targeting the Ad26 vector was also evaluated.

Results

No vaccine-associated serious adverse events were recorded. The full- and half-dose BNT162b2 boosted anti-SARS-CoV-2 binding antibody levels (3.9- and 4.5-fold, respectively) and neutralizing antibody levels (4.4- and 10-fold). Binding and neutralizing antibodies following half-dose Ad26.COV2.S were not significantly boosted. Full-dose Ad26.COV2.S did not boost binding antibodies but slightly enhanced neutralizing antibodies (2.1-fold). ADCC was marginally increased only after a full-dose BNT162b2. T-cell responses followed a similar pattern to neutralizing antibodies. Six months post-boost, antibody and T-cell responses had waned to baseline levels. While we detected strong anti-vector immunity, there was no correlation between anti-vector immunity in Ad26.COV2.S recipients and spike-specific neutralizing antibody or T-cell responses post-Ad26.COV2.S boosting.

Conclusion

In the context of hybrid immunity, boosting with heterologous full- or half-dose BNT162b2 mRNA vaccine demonstrated superior immunogenicity 2 weeks post-vaccination compared to homologous Ad26.COV2.S, though rapid waning occurred by 12 weeks post-boost.

Trial Registration

South African National Clinical Trial Registry (SANCR): DOH-27-012022-7841.

Funding

South African Medical Research Council (SAMRC) and South African Department of Health (SA DoH).

High prevalence of SARS-CoV-2 antibodies in pregnant women after the second wave of infections in the inner-city of Johannesburg, Gauteng Province, South Africa

OBJECTIVES

After South Africa's second wave of COVID-19, this study estimated the SARS-CoV-2 seroprevalence among pregnant women in inner-city Johannesburg, South Africa.

METHODS

In this cross-sectional survey, 500 pregnant women who were non-COVID-19-vaccinated (aged ≥12 years) were enrolled, and demographic and clinical data were collected. Serum samples were tested using the Wantai SARS-CoV-2 spike antibody enzyme-linked immunosorbent assay and Roche Elecsys® anti-SARS-CoV-2 nucleocapsid antibody assays. Seropositivity was defined as SARS-CoV-2 antibodies on either (primary) or both (secondary) assays. Univariate Poisson regression assessed risk factors associated with seropositivity.

RESULTS

The median age was 27.4 years, and HIV prevalence was 26.7%. SARS-CoV-2 seroprevalence was 64.0% (95% confidence interval [CI]: 59.6-68.2%) on the primary and 54% (95% CI: 49.5-58.4%) on the secondary measure. Most (96.6%) women who were SARS-CoV-2-seropositive reported no symptoms. On the Roche assay, we detected lower seroprevalence among women living with HIV than women without HIV (48.9% vs 61.7%, P-value = 0.018), and especially low levels among women living with HIV with a clusters of differentiation 4 <350 cells/ml compared with women without immune suppression (22.2% vs 56.4%, prevalence rate ratio = 0.4; 95% CI: 0.2-0.9; P-value = 0.046).

CONCLUSION

Pregnant women attending routine antenatal care had a high SARS-CoV-2 seroprevalence after the second wave in South Africa, and most had asymptomatic infections. Seroprevalence surveys in pregnant women present a feasible method of monitoring the course of the pandemic over time.

Physiological mechanisms of the impact of heat during pregnancy and the clinical implications: review of the evidence from an expert group meeting

Many populations experience high seasonal temperatures. Pregnant women are considered vulnerable to extreme heat because ambient heat exposure has been linked to pregnancy complications including preterm birth and low birthweight. The physiological mechanisms that underpin these associations are poorly understood. We reviewed the existing research evidence to clarify the mechanisms that lead to adverse pregnancy outcomes in order to inform public health actions. A multi-disciplinary expert group met to review the existing evidence base and formulate a consensus regarding the physiological mechanisms that mediate the effect of high ambient temperature on pregnancy. A literature search was conducted in advance of the meeting to identify existing hypotheses and develop a series of questions and themes for discussion. Numerous hypotheses have been generated based on animal models and limited observational studies. There is growing evidence that pregnant women are able to appropriately thermoregulate; however, when exposed to extreme heat, there are a number of processes that may occur which could harm the mother or fetus including a reduction in placental blood flow, dehydration, and an inflammatory response that may trigger preterm birth. There is a lack of substantial evidence regarding the processes that cause heat exposure to harm pregnant women. Research is urgently needed to identify what causes the adverse outcomes in pregnancy related to high ambient temperatures so that the impact of climate change on pregnant women can be mitigated.

Arthroplastie trapézo-métacarpienne par rotation trapézo-métacarpienne en îlot. Étude anatomique et technique opératoire

INTRODUCTION

To correct trapezium dysplasia we propose a new surgical technique. The operation consists of a double osteotomy of the trapezium and of the first metacarpal base, thereby harvesting the trapezo-metacarpal joint en-bloc. Vascularization is via the radial artery pedicle divided at the first web level. The articular block is then rotated 180 degrees on the longitudinal axis of the thumb.

METHOD

An anatomic study was performed on six fresh cadaveric upper limbs. The radial artery was injected with colored latex, 5 cm above the wrist. The peri-articular vascular network was studied. The feasibility of harvesting and rotating the articular bloc after double osteotomy of the first metacarpal basis and the trapezium was also studied.

RESULTS

In all the cases, the radial artery was present with branches supplying the peri-articular vascular network. After double osteotomy of the metacarpal base and of the trapezium, the articular bloc was harvested and rotated by 180 degrees. We describe the surgical technique.

DISCUSSION AND CONCLUSION

The surgical technique has been confirmed with the first clinical cases. The double oblique osteotomy with rotation of the articular bloc corrects trapezium dysplasia and preserves first metacarpal abduction. This procedure appears to be a solution in cases of trapezium dysplasia associated with instability and early stage osteoarthritis.

[Vascularized bone transfers in the wrist and hand]

More and more vascularised bone transfer (VBT) sites, free or pedicled, in the wrist and hand have been described since the 1980s. In the distal forearm, two main VBT: the fibula and the iliac crest, are used for large bone loss (> 6 cm) or for radio-carpal reconstruction. We report our experience of radio-carpal reconstruction using the distal-radio-ulnar joint transfer. At the carpal level, VBT are essentially used for "difficult" scaphoid pseudarthrosis: osteonecrosis, sclerotic bone or failures of conventional grafts and for lunate necrosis. Two pedicled VBT are frequently used for the scaphoid, a graft harvested from the antero-medial part of the distal radius (Kuhlmann) or a graft harvested from the postero-lateral part of the distal radius (Zaidemberg). For the trapezo-metacarpal joint, two new articular pedicle transfers can be used in some cases of trapezo-metacarpal arthritis. At the hand level, VBT are used for distal bone loss, "en bout de chaîne". Bone vascularisation is indispensable to preserve sub-chondral bone and avoid articular destruction. In children VBT are necessary to preserve the growth cartilage.

[Linburg-Comstock syndrome. Epidemiologic and anatomic study, clinical applications]

The Linburg-Comstock (LC) syndrome is distinguished by the inability to actively flex the interphalangeal (IP) joint of the thumb without simultaneously flexing the distal IP joint of the index finger. Any resistance to this 'parasitic' reaction causes pain on the palmar side of the wrist or in the distal part of the forearm; this is due to an anomalous tendinous connection between the flexor pollicus longus (FPL) and the flexor digitorum profundus (FDP). An epidemiological study was carried out on 264 individuals (a total of 528 hands were examined), and the LC syndrome was found in 98 subjects (37%); women were more frequently affected than men, and bilaterally rather than unilaterally. In addition, we dissected 26 fresh cadaver upper limbs, and in seven cases found an anomalous connection between FPL and FDP. We also examined the case of a young violinist with bilateral LC syndrome, who complained of pain in the distal part of the left forearm after prolonged musical exercises. Surgical investigation determined a complete fusion between FPL and FDP of the index with a common tendon. Treatment consisted of splitting this common tendon to form two separate tendons, thereby permitting a certain degree of independence between the thumb and index finger, and which considerably improved the violinist's musical performance. A review of the literature showed that there was a large quantity of anatomical descriptions available on these types of connection. Certain publications also provide an extremely precise report on the anthropological significance of these anomalies.

[Anatomical study of interosseous flaps and the concept of postero-anterior interosseous flap. Preliminary report]

The postero-anterior interosseous flap uses the distal network of the posterior and anterior interosseous arteries. With this flap the authors would like to point out all the possibilities of reverse fascio-cutaneous flaps offered by the interosseus arteries. An anatomic study has been carried out with both a literature review and a cadaveric study. The authors studied the distal interosseous anatomy on 40 fresh upper arms after colored latex injection of the anterior interosseous artery near its origin. A distal anastomosis between anterior and posterior interosseous arteries was present in 38 cases. This anastomosis was situated at an average of 25 mm from the radio-carpal joint. The authors found the fascio-cutaneous artery branch of the anterior interosseous flap in 40 cases, but its origin is variable. Therefore, the anterior interosseous flap was possible in every case but the pedicle length was variable. The surgical technique must begin by a distal exploration of the vascular network. After this exploration the flap is chosen in function with the anatomic possibilities and the cutaneous defect. The authors have already used several kinds of reverse interosseous flap: anterior (6 cases), posterior (11 cases) and recently, postero-anterior (2 cases). With the postero-anterior flap the authors will show the large range of flap possibilities offered by the interosseous arteries for the cutaneous defects of the dorsum of the hand.

[Transmission of pronation-supination movements in the wrist]

The wrist plays an essential in role the transmission of pronosupination movements. The four main muscles responsible for these movements are situated above the radiocarpal joint. This anatomic configuration allows a passive movement: Radio Metacarpal Rotation or RMR which is analysed here. Radio Metacarpal Rotation varies according to grip and the couple which is applied distally. An apparatus has been designed to simultaneously measure the angle, the force of grip and the couple. Radio Metacarpal Rotation is firstly measured with the wrist relaxed (grip strength < 5 N) and a distally applied rotation couple of 0.2 N.m in the supination direction and 0.5 N.m in the pronation direction. Secondly, the patient is asked to maintain a grip strength between 80 N and 100 N, and a couple of 1 N.m is applied distally in each direction. One hundred wrists were evaluated. We have looked for the rotation centers of active pronosupination and Radio Metacarpal Rotation. A three dimensional motion analysis device was used (ELITE system). Thirty normal wrists were evaluated. An anatomic study of the radiocarpal ligaments stretched by Radio Metacarpal Rotation was carried out on ten cadaver wrists. When the wrist is relaxed: there is an average Radio Metacarpal Rotation of 42 degrees. This Radio Metacarpal Rotation is reduced when grip is tightened. We have defined a locking test based on these two parameters. This clinical test is represented by two curves on a graph. The active pronosupination center and the radio metacarpal center do not coincide. The center of active pronosupination is situated near the center of the ulnar head and the center of radio-metacarpal rotation is always more lateral. On the anatomical preparations, we found a helicoidal configuration of the radiocarpal ligaments: a ligamentous double helix pronosupination. Radio Metacarpal Rotation interferes with transmission of pronosupination movements. When the wrist is not well locked there is a large lateral sweeping between radius and scaphoid. This sliding at the level of the cartilage can head to development of osteoarthritis of the wrist with a horizontal scaphoid and the good cartilage results after proximal row carpectomy. Radio Metacarpal Rotation must be taken into account when a prothesis designing. We propose a wrist locking test. The results of this test are directly related to the capacity of the joint surfaces to transmit pronosupination movements. Radio Metacarpal Rotation shows the importance of the horizontal plane in the wrist and its essential role in the transmission of pronosupination movements.

[Arthroplasty of the wrist by island transfer of the inferior radio-ulnar joint]

In cases of advanced osteoarthritis of the wrist, in which the radiocarpal and midcarpal joint spaces have been destroyed, the authors propose island transfer of the distal radioulnar joint. They studied the blood supply of the distal radioulnar joint from the interosseous arteries on 40 fresh cadaver upper limbs. The anatomical study showed that the dorsal epiphyseal periosteal network was supplied by the lower perforator of the anterior interosseus artery in every case and by the posterior interosseous artery in 38 out of 40 cases. The distal radioulnar joint can be harvested "en bloc" and rotated 90 degrees so that the joint space can be placed in radio-carpal position while preserving its blood supply on the anterior interosseous pedicle. The authors describe their operating technique and present their first clinical case. This new operation represents a non prosthetic alternative to arthrodesis.