Nasal mucosal IgA levels against SARS-CoV-2 and seasonal coronaviruses are low in children but boosted by reinfection

Repeated coronavirus infections in childhood drive progressive maturation of systemic immune responses into adulthood. Analyses of immune responses in children have focused primarily upon systemic assessment but the importance of mucosal immunity is increasingly recognised. We studied virus-specific antibody responses in contemporaneous nasal swabs and blood samples from 99 children (4-15 years) and 28 adults (22-56 years), all of whom had prior SARS-CoV-2 infection. Whilst mucosal IgA titres against Influenza and Respiratory Syncytial virus were comparable between children and adults, those against all coronaviruses, including SARS-CoV-2, were lower in children. Mucosal IgA antibodies demonstrated comparable relative neutralisation capacity in both groups and retained activity against recent omicron variants such as XBB.1 which are highly evasive of IgG neutralisation. SARS-CoV-2 reinfection preferentially enhanced mucosal IgA responses whilst the impact of vaccination was more modest. Nasal IgA levels against coronaviruses thus display a pattern of incremental response to reinfection which likely determines the natural history of reinfection. This highlights the particular significance of developing mucosal vaccines against coronaviruses in children.

Immunological imprinting of humoral immunity to SARS-CoV-2 in children

Omicron variants of SARS-CoV-2 are globally dominant and infection rates are very high in children. We measure immune responses following Omicron BA.1/2 infection in children aged 6-14 years and relate this to prior and subsequent SARS-CoV-2 infection or vaccination. Primary Omicron infection elicits a weak antibody response with poor functional neutralizing antibodies. Subsequent Omicron reinfection or COVID-19 vaccination elicits increased antibody titres with broad neutralisation of Omicron subvariants. Prior pre-Omicron SARS-CoV-2 virus infection or vaccination primes for robust antibody responses following Omicron infection but these remain primarily focussed against ancestral variants. Primary Omicron infection thus elicits a weak antibody response in children which is boosted after reinfection or vaccination. Cellular responses are robust and broadly equivalent in all groups, providing protection against severe disease irrespective of SARS-CoV-2 variant. Immunological imprinting is likely to act as an important determinant of long-term humoral immunity, the future clinical importance of which is unknown.

mRNA or ChAd0x1 COVID-19 Vaccination of Adolescents Induces Robust Antibody and Cellular Responses With Continued Recognition of Omicron Following mRNA-1273

Children and adolescents generally experience mild COVID-19. However, those with underlying physical health conditions are at a significantly increased risk of severe disease. Here, we present a comprehensive analysis of antibody and cellular responses in adolescents with severe neuro-disabilities who received COVID-19 vaccination with either ChAdOx1 (n=6) or an mRNA vaccine (mRNA-1273, n=8, BNT162b2, n=1). Strong immune responses were observed after vaccination and antibody levels and neutralisation titres were both higher after two doses. Both measures were also higher after mRNA vaccination and were further enhanced by prior natural infection where one vaccine dose was sufficient to generate peak antibody response. Robust T-cell responses were generated after dual vaccination and were also higher following mRNA vaccination. Early T-cells were characterised by a dominant effector-memory CD4+ T-cell population with a type-1 cytokine signature with additional production of IL-10. Antibody levels were well-maintained for at least 3 months after vaccination and 3 of 4 donors showed measurable neutralisation titres against the Omicron variant. T-cell responses also remained robust, with generation of a central/stem cell memory pool and showed strong reactivity against Omicron spike. These data demonstrate that COVID-19 vaccines display strong immunogenicity in adolescents and that dual vaccination, or single vaccination following prior infection, generate higher immune responses than seen after natural infection and develop activity against Omicron. Initial evidence suggests that mRNA vaccination elicits stronger immune responses than adenoviral delivery, although the latter is also higher than seen in adult populations. COVID-19 vaccines are therefore highly immunogenic in high-risk adolescents and dual vaccination might be able to provide relative protection against the Omicron variant that is currently globally dominant.

Emergence of the delta variant and risk of SARS-CoV-2 infection in secondary school students and staff: Prospective surveillance in 18 schools, England

BACKGROUND

The role of educational settings in SARS-CoV-2 infection and transmission remains controversial. We investigated SARS-CoV-2 infection, seroprevalence, and seroconversion rates in secondary schools during the 2020/21 academic year, which included the emergence of the more transmissible alpha and delta variants, in England.

METHODS

The UK Health Security Agency (UKHSA) initiated prospective surveillance in 18 urban English secondary schools. Participants had nasal swabs for SARS-CoV-2 RT-PCR and blood sampling for SARS-CoV-2 nucleoprotein and spike protein antibodies at the start (Round 1: September-October 2020) and end (Round 2: December 2020) of the autumn term, when schools reopened after national lockdown was imposed in January 2021 (Round 3: March-April 2021), and end of the academic year (Round 4: May-July 2021).

FINDINGS

We enrolled 2314 participants (1277 students, 1037 staff; one participant had missing data for PCR testing). In-school testing identified 31 PCR-positive participants (20 students, 11 staff). Another 247 confirmed cases (112 students, 135 staff) were identified after linkage with national surveillance data, giving an overall positivity rate of 12.0% (278/2313; staff: 14.1%, 146/1037 vs students: 10.3%, 132/1276; p = 0.006). Trends were similar to national infection data. Nucleoprotein-antibody seroprevalence increased for students and staff between Rounds 1 and 3 but were similar between Rounds 3 and 4, when the delta variant was the dominant circulating strain. Overall, Nucleoprotein-antibody seroconversion was 18.4% (137/744) in staff and 18.8% (146/778) in students, while Spike-antibody seroconversion was higher in staff (72.8%, 525/721) than students (21.3%, 163/764) because of vaccination.

INTERPRETATION

SARS-CoV-2 infection rates in secondary schools remained low when community infection rates were low, even as the delta variant was emerging in England.

FUNDING

This study was funded by the UK Department of Health and Social Care.

SARS Antibody Testing in Children: Development of Oral Fluid Assays for IgG Measurements

Seroepidemiological studies to monitor antibody kinetics are important for assessing the extent and spread of SARS-CoV-2 in a population. Noninvasive sampling methods are advantageous for reducing the need for venipuncture, which may be a barrier to investigations, particularly in pediatric populations. Oral fluids are obtained by gingiva-crevicular sampling from children and adults and are very well accepted. Enzyme immunoassays (EIAs) based on these samples have acceptable sensitivity and specificity compared to conventional serum-based antibody EIAs and are suitable for population-based surveillance. We describe the development and evaluation of SARS-CoV-2 IgG EIAs using SARS-CoV-2 viral nucleoprotein (NP) and spike (S) proteins in IgG isotype capture format and an indirect receptor-binding-domain (RBD) IgG EIA, intended for use in children as a primary endpoint. All three assays were assessed using a panel of 1,999 paired serum and oral fluids from children and adults participating in school SARS-CoV-2 surveillance studies during and after the first and second pandemic wave in the United Kingdom. The anti-NP IgG capture assay was the best candidate, with an overall sensitivity of 75% (95% confidence interval [CI]: 71 to 79%) and specificity of 99% (95% CI: 78 to 99%) compared with paired serum antibodies. Sensitivity observed in children (80%, 95% CI: 71 to 88%) was higher than that in adults (67%, CI: 60% to 74%). Oral fluid assays (OF) using spike protein and RBD antigens were also 99% specific and achieved reasonable but lower sensitivity in the target population (78%, 95% CI [68% to 86%] and 53%, 95% CI [43% to 64%], respectively). IMPORTANCE We report on the first large-scale assessment of the suitability of oral fluids for detection of SARS-CoV-2 antibody obtained from healthy children attending school. The sample type (gingiva-crevicular fluid, which is a transudate of blood but is not saliva) can be self collected. Although detection of antibodies in oral fluids is less sensitive than that in blood, our study suggests an optimal format for operational use. The laboratory methods we have developed can reliably measure antibodies in children, who are able to take their own samples. Our findings are of immediate practical relevance for use in large-scale seroprevalence studies designed to measure exposure to infection, as they typically require venipuncture. Overall, our data indicate that OF assays based on the detection of SARS-CoV-2 antibodies are a tool suitable for population-based seroepidemiology studies in children and highly acceptable in children and adults, as venipuncture is no longer necessary.

Children develop robust and sustained cross-reactive spike-specific immune responses to SARS-CoV-2 infection

SARS-CoV-2 infection is generally mild or asymptomatic in children but a biological basis for this outcome is unclear. Here we compare antibody and cellular immunity in children (aged 3-11 years) and adults. Antibody responses against spike protein were high in children and seroconversion boosted responses against seasonal Beta-coronaviruses through cross-recognition of the S2 domain. Neutralization of viral variants was comparable between children and adults. Spike-specific T cell responses were more than twice as high in children and were also detected in many seronegative children, indicating pre-existing cross-reactive responses to seasonal coronaviruses. Importantly, children retained antibody and cellular responses 6 months after infection, whereas relative waning occurred in adults. Spike-specific responses were also broadly stable beyond 12 months. Therefore, children generate robust, cross-reactive and sustained immune responses to SARS-CoV-2 with focused specificity for the spike protein. These findings provide insight into the relative clinical protection that occurs in most children and might help to guide the design of pediatric vaccination regimens.

Antibody persistence and neutralising activity in primary school students and staff: Prospective active surveillance, June to December 2020, England

BACKGROUND

Prospective, longitudinal SARS-CoV-2 sero-surveillance in schools across England was initiated after the first national lockdown, allowing comparison of child and adult antibody responses over time.

METHODS

Prospective active serological surveillance in 46 primary schools in England tested for SARS-CoV-2 antibodies during June, July and December 2020. Samples were tested for nucleocapsid (N) and receptor binding domain (RBD) antibodies, to estimate antibody persistence at least 6 months after infection, and for the correlation of N, RBD and live virus neutralising activity.

FINDINGS

In June 2020, 1,344 staff and 835 students were tested. Overall, 11.5% (95%CI: 9.4-13.9) and 11.3% (95%CI: 9.2-13.6; p = 0.88) of students had nucleoprotein and RBD antibodies, compared to 15.6% (95%CI: 13.7-17.6) and 15.3% (95%CI: 13.4-17.3; p = 0.83) of staff. Live virus neutralising activity was detected in 79.8% (n = 71/89) of nucleocapsid and 85.5% (71/83) of RBD antibody positive children. RBD antibodies correlated more strongly with neutralising antibodies (rs=0.7527; p<0.0001) than nucleocapsid antibodies (rs=0.3698; p<0.0001). A median of 24.4 weeks later, 58.2% (107/184) participants had nucleocapsid antibody seroreversion, compared to 20.9% (33/158) for RBD (p<0.001). Similar seroreversion rates were observed between staff and students for nucleocapsid (p = 0.26) and RBD-antibodies (p = 0.43). Nucleocapsid and RBD antibody quantitative results were significantly lower in staff compared to students (p = 0.028 and <0.0001 respectively) at baseline, but not at 24 weeks (p = 0.16 and p = 0.37, respectively).

INTERPRETATION

The immune response in children following SARS-CoV-2 infection was robust and sustained (>6 months) but further work is required to understand the extent to which this protects against reinfection.

Feasibility and acceptability of SARS-CoV-2 testing and surveillance in primary school children in England: Prospective, cross-sectional study

BACKGROUND

The reopening of schools during the COVID-19 pandemic has raised concerns about widespread infection and transmission of SARS-CoV-2 in educational settings. In June 2020, Public Health England (PHE) initiated prospective national surveillance of SARS-CoV-2 in primary schools across England (sKIDs). We used this opportunity to assess the feasibility and agreeability of large-scale surveillance and testing for SARS-CoV-2 infections in school among staff, parents and students.

METHODS

Staff and students in 131 primary schools were asked to complete a questionnaire at recruitment and provide weekly nasal swabs for SARS-CoV-2 RT-PCR testing (n = 86) or swabs with blood samples for antibody testing (n = 45) at the beginning and end the summer half-term. In six blood sampling schools, students were asked to complete a pictorial questionnaire before and after their investigations.

RESULTS

In total, 135 children aged 4-7 years (n = 40) or 8-11 years (n = 95) completed the pictorial questionnaire fully or partially. Prior to sampling, oral fluid sampling was the most acceptable test (107/132, 81%) followed by throat swabs (80/134, 59%), nose swabs (77/132, 58%), and blood tests (48/130, 37%). Younger students were more nervous about all tests than older students but, after completing their tests, most children reported a "better than expected" experience with all the investigations. Students were more likely to agree to additional testing for nose swabs (93/113, 82%) and oral fluid (93/114, 82%), followed by throat swabs (85/113, 75%) and blood tests (72/108, 67%). Parents (n = 3,994) and staff (n = 2,580) selected a preference for weekly testing with nose swabs, throat swabs or oral fluid sampling, although staff were more flexible about testing frequency.

CONCLUSIONS

Primary school staff and parents were supportive of regular tests for SARS-CoV-2 and selected a preference for weekly testing. Children preferred nose swabs and oral fluids over throat swabs or blood sampling.

Emergence of SARS-CoV-2 Alpha (B.1.1.7) variant, infection rates, antibody seroconversion and seroprevalence rates in secondary school students and staff: Active prospective surveillance, December 2020 to March 2021, England

Objectives

We assessed SARS-CoV-2 infection, seroprevalence and seroconversion in students and staff when secondary schools reopened in March 2021.

Methods

We initiated SARS-CoV-2 surveillance in 18 secondary schools across six regions in September 2020. Participants provided nasal swabs for RT-PCR and blood samples for SARS-CoV-2 antibodies at the beginning (September 2020) and end (December 2020) of the autumn term and at the start of the spring term (March 2021).

Findings

In March 2021, 1895 participants (1100 students:795 staff) were tested; 5.6% (61/1094) students and 4.4% (35/792) staff had laboratory-confirmed SARS-CoV-2 infection from December 2020-March 2021. Nucleoprotein-antibody seroprevalence was 36.3% (370/1018) in students and 31.9% (245/769) in staff, while spike-antibody prevalence was 39.5% (402/1018) and 59.8% (459/769), respectively, similar to regional community seroprevalence. Between December 2020 and March 2021, 14.8% (97/656; 95%CI: 12.2–17.7) students and 10.0% (59/590; 95%CI: 7.7–12.7) staff seroconverted. Weekly seroconversion rates were similar from September to December 2020 (8.0/1000) and from December 2020 to March 2021 (7.9/1000; students: 9.3/1,000; staff: 6.3/1,000).

Interpretation

By March 2021, a third of secondary school students and staff had evidence of prior infection based on N-antibody seropositivity, and an additional third of staff had evidence of vaccine-induced immunity based on S-antibody seropositivity.

SARS-CoV-2 infection, antibody positivity and seroconversion rates in staff and students following full reopening of secondary schools in England: A prospective cohort study, September-December 2020

BACKGROUND

Older children have higher SARS-CoV-2 infection rates than younger children. We investigated SARS-CoV-2 infection, seroprevalence and seroconversion rates in staff and students following the full reopening of all secondary schools in England.

METHODS

Public Health England (PHE) invited secondary schools in six regions (East and West London, Hertfordshire, Derbyshire, Manchester and Birmingham) to participate in SARS-CoV-2 surveillance during the 2020/21 academic year. Participants had nasal swabs for RT-PCR and blood samples for SARS-CoV-2 antibodies at the beginning (September 2020) and end (December 2020) of the autumn term. Multivariable logistic regression was used to assess independent risk factors for seropositivity and seroconversion.

FINDINGS

Eighteen schools in six regions enrolled 2,209 participants, including 1,189 (53.8%) students and 1,020 (46.2%) staff. SARS-CoV-2 infection rates were not significantly different between students and staff in round one (5/948; [0.53%] vs. 2/876 [0.23%]; p = 0.46) or round two (10/948 [1.05%] vs. 7/886 [0.79%]; p = 0.63), and similar to national prevalence. None of four and 7/15 (47%) sequenced strains in rounds 1 and 2 were the highly transmissible SARS-CoV-2 B.1.1.7 variant. In round 1, antibody seropositivity was higher in students than staff (114/893 [12.8%] vs. 79/861 [9.2%]; p = 0.016), but similar in round 2 (117/893 [13.1%] vs.117/872 [13.3%]; p = 0.85), comparable to local community seroprevalence. Between the two rounds, 8.7% (57/652) staff and 6.6% (36/549) students seroconverted (p = 0.16).

INTERPRETATION

In secondary schools, SARS-CoV-2 infection, seropositivity and seroconversion rates were similar in staff and students, and comparable to local community rates. Ongoing surveillance will be important for monitoring the impact of new variants in educational settings.

SARS-CoV-2 infection and transmission in primary schools in England in June-December, 2020 (sKIDs): an active, prospective surveillance study

BACKGROUND

Little is known about the risk of SARS-CoV-2 infection and transmission in educational settings. Public Health England initiated a study, COVID-19 Surveillance in School KIDs (sKIDs), in primary schools when they partially reopened from June 1, 2020, after the first national lockdown in England to estimate the incidence of symptomatic and asymptomatic SARS-CoV-2 infection, seroprevalence, and seroconversion in staff and students.

METHODS

sKIDs, an active, prospective, surveillance study, included two groups: the weekly swabbing group and the blood sampling group. The swabbing group underwent weekly nasal swabs for at least 4 weeks after partial school reopening during the summer half-term (June to mid-July, 2020). The blood sampling group additionally underwent blood sampling for serum SARS-CoV-2 antibodies to measure previous infection at the beginning (June 1-19, 2020) and end (July 3-23, 2020) of the summer half-term, and, after full reopening in September, 2020, and at the end of the autumn term (Nov 23-Dec 18, 2020). We tested for predictors of SARS-CoV-2 antibody positivity using logistic regression. We calculated antibody seroconversion rates for participants who were seronegative in the first round and were tested in at least two rounds.

FINDINGS

During the summer half-term, 11 966 participants (6727 students, 4628 staff, and 611 with unknown staff or student status) in 131 schools had 40 501 swabs taken. Weekly SARS-CoV-2 infection rates were 4·1 (one of 24 463; 95% CI 0·1-21·8) per 100 000 students and 12·5 (two of 16 038; 1·5-45·0) per 100 000 staff. At recruitment, in 45 schools, 91 (11·2%; 95% CI 7·9-15·1) of 816 students and 209 (15·1%; 11·9-18·9) of 1381 staff members were positive for SARS-CoV-2 antibodies, similar to local community seroprevalence. Seropositivity was not associated with school attendance during lockdown (p=0·13 for students and p=0·20 for staff) or staff contact with students (p=0·37). At the end of the summer half-term, 603 (73·9%) of 816 students and 1015 (73·5%) of 1381 staff members were still participating in the surveillance, and five (four students, one staff member) seroconverted. By December, 2020, 55 (5·1%; 95% CI 3·8-6·5) of 1085 participants who were seronegative at recruitment (in June, 2020) had seroconverted, including 19 (5·6%; 3·4-8·6) of 340 students and 36 (4·8%; 3·4-6·6) of 745 staff members (p=0·60).

INTERPRETATION

In England, SARS-CoV-2 infection rates were low in primary schools following their partial and full reopening in June and September, 2020.

FUNDING

UK Department of Health and Social Care.

Assessment of Myocardial Function in Kenyan Children With Severe, Acute Malnutrition: The Cardiac Physiology in Malnutrition (CAPMAL) Study

Importance

Mortality among African children hospitalized with severe malnutrition remains high, with sudden, unexpected deaths leading to speculation about potential cardiac causes. Malnutrition is considered high risk for cardiac failure, but evidence is limited.

Objective

To investigate the role of cardiovascular dysfunction in African children with severe, acute malnutrition (SAM).

Design, Setting, and Participants

A prospective, matched case-control study, the Cardiac Physiology in Malnutrition (CAPMAL) study, of 88 children with SAM (exposed) vs 22 severity-matched patients without SAM (unexposed) was conducted between March 7, 2011, and February 20, 2012; data analysis was performed from October 1, 2012, to March 1, 2016.

Exposures

Echocardiographic and electrocardiographic (ECG) recordings (including 7-day Holter monitoring) at admission, day 7, and day 28.

Main Outcomes and Measures

Findings in children with (cases) and without (controls) SAM and in marasmus and kwashiorkor phenotypes were compared.

Results

Eighty-eight children (52 with marasmus and 36 with kwashiorkor) of the 418 admitted with SAM and 22 severity-matched controls were studied. A total of 63 children (57%) were boys; median age at admission was 19 months (range, 12-39 months). On admission, abnormalities more common in cases vs controls included severe hypokalemia (potassium <2.5 mEq/L) (18 of 81 [22%] vs 0%), hypoalbuminemia (albumin level <3.4 g/dL) (66 of 88 [75%] vs 4 of 22 [18%]), and hypothyroidism (free thyroxine level <0.70 ng/dL or thyrotropin level >4.2 mU/L) (18 of 74 [24%] vs 1 of 21 [5%]) and were associated with typical electrocardiographic changes (T-wave inversion: odds ratio, 7.3; 95% CI, 1.9-28.0; P = .001), which corrected as potassium levels improved. Fourteen children with SAM (16%) but no controls died. Myocardial mass was lower in cases on admission but not by day 7. Results of the Tei Index, a measure of global cardiac function, were within the reference range and similar in cases (median, 0.37; interquartile range [IQR], 0.26-0.45) and controls (median, 0.36; IQR, 0.28-0.42). Echocardiography detected no evidence of cardiac failure among children with SAM, including those receiving intravenous fluids to correct hypovolemia. Cardiac dysfunction was generally associated with comorbidity and typical of hypovolemia, with low cardiac index (median, 4.9 L/min/m2; IQR, 3.9-6.1 L/min/m2), high systemic vascular resistance index (median, 1333 dyne seconds/cm5/m2; IQR, 1133-1752 dyne seconds/cm5/m2), and with few differences between the marasmus and kwashiorkor manifestations of malnutrition. Seven-day continuous ECG Holter monitoring during the high-risk initial refeeding period demonstrated self-limiting significant ventricular arrhythmias in 33 of 55 cases (60%) and 6 of 18 controls (33%) (P = .049); none were temporally related to adverse events, including fatalities.

Conclusions and Relevance

There is little evidence that African children with SAM are at greater risk of cardiac dysfunction or clinically significant arrhythmias than those without SAM or that marasmus and kwashiorkor differed in cardiovascular profile. These findings should prompt a review of current guidelines.

Myocardial and haemodynamic responses to two fluid regimens in African children with severe malnutrition and hypovolaemic shock (AFRIM study)

BACKGROUND

Fluid therapy in severely malnourished children is hypothesized to be deleterious owing to compromised cardiac function. We evaluated World Health Organization (WHO) fluid resuscitation guidelines for hypovolaemic shock using myocardial and haemodynamic function and safety endpoints.

METHODS

A prospective observational study of two sequential fluid management strategies was conducted at two East African hospitals. Eligible participants were severely malnourished children, aged 6-60 months, with hypovolaemic shock secondary to gastroenteritis. Group 1 received up to two boluses of 15 ml/kg/h of Ringer's lactate (RL) prior to rehydration as per WHO guidelines. Group 2 received rehydration only (10 ml/kg/h of RL) up to a maximum of 5 h. Comprehensive clinical, haemodynamic and echocardiographic data were collected from admission to day 28.

RESULTS

Twenty children were enrolled (11 in group 1 and 9 in group 2), including 15 children (75%) with kwashiorkor, 8 (40%) with elevated brain natriuretic peptide >300 pg/ml, and 9 (45%) with markedly elevated median systemic vascular resistance index (SVRI) >1600 dscm-5/m2 indicative of severe hypovolaemia. Echocardiographic evidence of fluid-responsiveness (FR) was heterogeneous in group 1, with both increased and decreased stroke volume and myocardial fractional shortening. In group 2, these variables were more homogenous and typical of FR. Median SVRI marginally decreased post fluid administration (both groups) but remained high at 24 h. Mortality at 48 h and to day 28, respectively, was 36% (4 deaths) and 81.8% (9 deaths) in group 1 and 44% (4 deaths) and 55.6% (5 deaths) in group 2. We observed no pulmonary oedema or congestive cardiac failure on or during admission; most deaths were unrelated to fluid interventions or echocardiographic findings of response to fluids.

CONCLUSION

Baseline and cardiac response to fluid resuscitation do not indicate an effect of compromised cardiac function on response to fluid loading or that fluid overload is common in severely malnourished children with hypovolaemic shock. Endocrine response to shock and persistently high SVRI post fluid-therapy resuscitation may indicate a need for further research investigating enhanced fluid volumes to adequately correct volume deficit. The adverse outcomes are concerning, but appear to be unrelated to immediate fluid management.

Exploring mechanisms of excess mortality with early fluid resuscitation: insights from the FEAST trial

BACKGROUND

Early rapid fluid resuscitation (boluses) in African children with severe febrile illnesses increases the 48-hour mortality by 3.3% compared with controls (no bolus). We explored the effect of boluses on 48-hour all-cause mortality by clinical presentation at enrolment, hemodynamic changes over the first hour, and on different modes of death, according to terminal clinical events. We hypothesize that boluses may cause excess deaths from neurological or respiratory events relating to fluid overload.

METHODS

Pre-defined presentation syndromes (PS; severe acidosis or severe shock, respiratory, neurological) and predominant terminal clinical events (cardiovascular collapse, respiratory, neurological) were described by randomized arm (bolus versus control) in 3,141 severely ill febrile children with shock enrolled in the Fluid Expansion as Supportive Therapy (FEAST) trial. Landmark analyses were used to compare early mortality in treatment groups, conditional on changes in shock and hypoxia parameters. Competing risks methods were used to estimate cumulative incidence curves and sub-hazard ratios to compare treatment groups in terms of terminal clinical events.

RESULTS

Of 2,396 out of 3,141 (76%) classifiable participants, 1,647 (69%) had a severe metabolic acidosis or severe shock PS, 625 (26%) had a respiratory PS and 976 (41%) had a neurological PS, either alone or in combination. Mortality was greatest among children fulfilling criteria for all three PS (28% bolus, 21% control) and lowest for lone respiratory (2% bolus, 5% control) or neurological (3% bolus, 0% control) presentations. Excess mortality in bolus arms versus control was apparent for all three PS, including all their component features. By one hour, shock had resolved (responders) more frequently in bolus versus control groups (43% versus 32%, P <0.001), but excess mortality with boluses was evident in responders (relative risk 1.98, 95% confidence interval 0.94 to 4.17, P = 0.06) and 'non-responders' (relative risk 1.67, 95% confidence interval 1.23 to 2.28, P = 0.001), with no evidence of heterogeneity (P = 0.68). The major difference between bolus and control arms was the higher proportion of cardiogenic or shock terminal clinical events in bolus arms (n = 123; 4.6% versus 2.6%, P = 0.008) rather than respiratory (n = 61; 2.2% versus 1.3%, P = 0.09) or neurological (n = 63, 2.1% versus 1.8%, P = 0.6) terminal clinical events.

CONCLUSIONS

Excess mortality from boluses occurred in all subgroups of children. Contrary to expectation, cardiovascular collapse rather than fluid overload appeared to contribute most to excess deaths with rapid fluid resuscitation. These results should prompt a re-evaluation of evidence on fluid resuscitation for shock and a re-appraisal of the rate, composition and volume of resuscitation fluids.

TRIAL REGISTRATION

ISRCTN69856593.

Mortality after fluid bolus in African children with severe infection

BACKGROUND

The role of fluid resuscitation in the treatment of children with shock and life-threatening infections who live in resource-limited settings is not established.

METHODS

We randomly assigned children with severe febrile illness and impaired perfusion to receive boluses of 20 to 40 ml of 5% albumin solution (albumin-bolus group) or 0.9% saline solution (saline-bolus group) per kilogram of body weight or no bolus (control group) at the time of admission to a hospital in Uganda, Kenya, or Tanzania (stratum A); children with severe hypotension were randomly assigned to one of the bolus groups only (stratum B). All children received appropriate antimicrobial treatment, intravenous maintenance fluids, and supportive care, according to guidelines. Children with malnutrition or gastroenteritis were excluded. The primary end point was 48-hour mortality; secondary end points included pulmonary edema, increased intracranial pressure, and mortality or neurologic sequelae at 4 weeks.

RESULTS

The data and safety monitoring committee recommended halting recruitment after 3141 of the projected 3600 children in stratum A were enrolled. Malaria status (57% overall) and clinical severity were similar across groups. The 48-hour mortality was 10.6% (111 of 1050 children), 10.5% (110 of 1047 children), and 7.3% (76 of 1044 children) in the albumin-bolus, saline-bolus, and control groups, respectively (relative risk for saline bolus vs. control, 1.44; 95% confidence interval [CI], 1.09 to 1.90; P=0.01; relative risk for albumin bolus vs. saline bolus, 1.01; 95% CI, 0.78 to 1.29; P=0.96; and relative risk for any bolus vs. control, 1.45; 95% CI, 1.13 to 1.86; P=0.003). The 4-week mortality was 12.2%, 12.0%, and 8.7% in the three groups, respectively (P=0.004 for the comparison of bolus with control). Neurologic sequelae occurred in 2.2%, 1.9%, and 2.0% of the children in the respective groups (P=0.92), and pulmonary edema or increased intracranial pressure occurred in 2.6%, 2.2%, and 1.7% (P=0.17), respectively. In stratum B, 69% of the children (9 of 13) in the albumin-bolus group and 56% (9 of 16) in the saline-bolus group died (P=0.45). The results were consistent across centers and across subgroups according to the severity of shock and status with respect to malaria, coma, sepsis, acidosis, and severe anemia.

CONCLUSIONS

Fluid boluses significantly increased 48-hour mortality in critically ill children with impaired perfusion in these resource-limited settings in Africa. (Funded by the Medical Research Council, United Kingdom; FEAST Current Controlled Trials number, ISRCTN69856593.).

Subarachnoid hemorrhage incidence among Whites, Blacks and Caribbean Hispanics: the Northern Manhattan Study

American blacks and Hispanics may have a greater incidence of subarachnoid hemorrhage (SAH) than whites, but incidence data are scant. We used an active hospital and community surveillance program and autopsy reports to identify incident SAH cases among white, black and Hispanic adults living in Northern Manhattan between July 1993 and June 1997. The annual incidence adjusted for age and sex to the 1990 US Census was 9.7 per 100,000 (95% CI 7.5-12.0). Compared with whites (9 cases, age- and sex-adjusted annual incidence 8.2 per 100,000), the rate ratio of SAH was 1.3 (95% CI 0.7-2.4) for Hispanics (34 cases, incidence 10.9), and 1.6 (95% CI 0.8-2.8) for blacks (9 cases, incidence 12.8). The 30-day case fatality rate was 26%. Risk of death increased significantly with age and severity at onset but was not influenced by gender or race-ethnicity.

The team approach to treating the microtia atresia patient

For optimal function and esthetic results in the microtia/atresia patient, an integrated team approach between the plastic surgeon and the otologic surgeon is essential. This article addresses this complex management problem by drawing on the author's experience with more than 1000 microtia patients. This article elucidates an optimal strategy for integrated patient care that has been developed in conjunction with several experienced otologists over the past 25 years.

Transforming growth factor beta superfamily members: role in cartilage modeling

Normal and abnormal extracellular matrix turnover is thought to result, in part, from the balance in the expression of metalloproteinases and tissue inhibitors of metalloproteinases (TIMPs). The clinical manifestations of an imbalance in these relationships are evident in a variety of pathologic states, including osteoarthritis, deficient long-bone growth, rheumatoid arthritis, tumor invasion, and inadequate cartilage repair. Articular cartilage defects commonly heal as fibrocartilage, which is structurally inferior to the normal hyaline architecture of articular cartilage. Transforming growth factor-beta 1 (TGF-beta1), a cytokine central to growth, repair, and inflammation, has been shown to upregulate TIMP-1 expression in human and bovine articular cartilage. Additionally, members of the TGF-beta superfamily are thought to play key roles in chondrocyte growth and differentiation. Bone morphogenetic protein-2 (BMP-2), a member of this superfamily, has been shown to regulate chondrocyte differentiation states and extracellular matrix composition. It was proposed that, by optimizing extracellular matrix composition, BMP-2 would enhance articular cartilage healing. After determining the release kinetics of BMP-2 from a collagen type I implant (Long-Evans male rats; two implants/rat, n = 14), it was found that, in a tissue engineering application, BMP-2 induced a hyaline-like repair of New Zealand White rabbit knee articular cartilage defects (3-mm full-thickness defects in the femoral trochlea; 2 defects/rabbit, n = 36). The quality of cartilage repair with BMP-2 (with or without chondrocytes) was significantly better than defects treated with BMP-2, as assessed by a quantitative scoring scale. Immunohistochemical staining revealed TIMP-1 production in the cartilage defects treated with BMP-2. When studied in vitro, it was found that BMP-2 markedly increased TIMP-1 mRNA by both bovine articular and human rib chondrocytes. Additionally, increased TIMP-1 mRNA was translated into increased TIMP-1 protein production by bovine chondrocytes. Taken together, these data suggest that BMP-2 may be a useful cytokine to improve healing of cartilaginous defects. Furthermore, these data suggest that the beneficial effects of BMP-2 may be, in part, related to alterations in extracellular matrix turnover.

Technical advances in ear reconstruction with autogenous rib cartilage grafts: personal experience with 1200 cases

Through the author's experience with 1200 cases during a 25-year period, this article presents technical improvements in ear reconstruction and proposes and discusses possible directions for further technical advancement. This article presents the rationale for the author's current methods of managing total ear repair. Throughout the article, the author stresses and demonstrates cartilage-sparing techniques that are designed to minimize the amount of cartilage used in a repair to preserve maximum chest wall integrity. This article also presents the latest method of framework fabrication, showing differences in construction between younger and older patients; a new method that constructs a tragus as an integral part of the framework; a method that maintains ear projection with a scalp-banked cartilage wedge; and a method that solves the always frustrating low hairline by presurgical laser treatment. In addition, the concept of creating autogenous frameworks by tissue engineering is pursued and discussed in practical clinical terms. A survey of 1000 microtia patients indicates that surgically constructed ears remain durable, withstand trauma well, and provide consistent emotional relief and psychological benefits through the repair.

Human cartilage engineering: chondrocyte extraction, proliferation, and characterization for construct development

To date, many efforts to engineer cartilage have focused on matrix construction with the goal of producing a durable construct as cartilage replaces the resorbing matrix. However, the importance of matrix construction is at least matched by the challenge of efficient chondrocyte extraction, culture expansion, and prevention of dedifferentiation. This challenge is underscored by the large number of chondrocytes needed for a clinically significant construct such as an ear. Because human rib provides a large, readily available source of hyaline cartilage, the authors evaluated human rib chondrocyte extraction and found that maximum viable cell yield occurred after a 6-hour digestion. They also evaluated human microtic auricular remnant chondrocyte extraction and identified fibroblast contamination as a shortcoming of this potential source of chondrocytes. Initially, rib chondrocytes proliferated in vitro with a doubling time of approximately 1 week. As the cells were passaged, proliferation decreased such that the cells stopped proliferating and adopted a large, spindle-shaped morphology by passage 6. Interestingly, no increase in proliferation was noted when rib chondrocytes were stimulated with transforming growth factor beta 1, bone morphogenetic protein 2, and basic fibroblast growth factor. The major obstacles to the use of autologous rib chondrocytes in matrix construction are the low cell yield from a small piece of rib and the limited proliferation that these cells will undergo in vitro. Further investigation of culture systems and mitogenic cytokines may help resolve these limitations.

Auricular repair with autogenous rib cartilage grafts: two decades of experience with 600 cases

The purpose of this paper is twofold: to present a sound approach to auricular construction using methods that have evolved through two decades of my personal experience with 600 cases and to discuss pertinent information I have gleaned from a questionnaire sent to my operated patients. This series comprises 546 completed ears in 500 microtia patients (46 bilateral) and 75 completed ears in acquired deformities. Follow-up ranges from 1 to 17 years. Major complications such as infection, hematoma, or skin loss with cartilage exposure occurred in only 1.6 percent of cases and were limited to the perioperative period of 12 days. None have occurred in the last 9 years (481 frameworks). This paper describes the evolution and rationale for my current management of total ear repair and covers preoperative planning, how to fabricate the rib cartilage framework, how to modify the framework for specific deformities, and how to cover the framework, i.e., how to assess and use local skin and vestiges or when to supplement the coverage by recruiting fascial flaps or using tissue expansion. When considering fascial flaps, patient selection was found to be particularly important because of long-term effects on the donor scalp; expansion was found to be most useful intraoperatively. This paper also covers how to manage the hairline, how to stage the surgery, when to combine procedures, and how to manage bilateral microtia in a team approach. The survey revealed that autogenous cartilage frameworks grow, are durable, retain their detail over the years, and withstand trauma well. More than 40 severe traumas occurred in surgically constructed ears, and all healed without incident. Ears constructed in young patients generally grew to keep pace with the opposite normal side; 41.6 percent actually overgrew by several millimeters. Emotional and psychological benefits were universal, and patient satisfaction was high. Among patients who were classified as "severely affected" by the original deformity, 100 percent were pleased with the result. When considered "moderately disturbed" by the microtic defect and operated on by age 14, 95.5 percent of patients were satisfied with the surgical repair; 83.3 percent of adolescents between the ages of 15 and 20 who did not consider themselves "severely affected" by the deformity were pleased with the outcome, and the rest were "undecided."

A perceived cluster of amyotrophic lateral sclerosis cases in a Massachusetts community

We investigated a report of a perceived cluster of amyotrophic lateral sclerosis (ALS) in Middleborough, Mass. Although an increase in ALS incidence was observed [2.51 deaths/100,000 person-years (p-y)], relative to the statewide rate over the years 1969-1985 (1.26/100,000 p-y), it was not statistically significant at the 95% confidence level. Problems in evaluating possible neurological disease clusters and their association with environmental exposures are presented.

Short-duration, high-dose urokinase infusion for recanalization of occluded saphenous aortocoronary bypass grafts

Thrombolytic recanalization of arterial bypass grafts has been pursued aggressively in the peripheral circulation but not in the coronary circulation. In an attempt to apply peripheral transcatheter thrombolytic techniques to the coronary circulation, nine patients with 10 occluded saphenous aortocoronary bypass grafts underwent recanalization procedures using a short-duration, high-dose urokinase infusion. Urokinase was infused at the occluded graft orifice at a rate of 600 units/min. The average infusion time was 1 hr, 26 min. The average urokinase dose was 435,000 units. Graft recanalization was achieved in eight (80%) of 10 grafts, although only six (60%) of 10 grafts were widely patent at the end of the procedure. All successfully recanalized grafts required balloon angioplasty of underlying stenoses. No complications, specifically myocardial infarction or cerebrovascular accident, were encountered. We have shown that occluded aortocoronary bypass grafts can be recanalized successfully by using a short-duration, high-dose urokinase infusion. It appears that, with attention given to angiographic techniques that minimize clot manipulation, recanalization can be accomplished safely in a majority of cases.

Experience with the temporoparietal fascial free flap

The temporoparietal fascia is an ideal tissue source for free transfer to distant sites where ultrathin coverage is either desirable or mandatory. The fascia's dependable vascular anatomy facilitates the technical aspects of microvascular transfer by means of its large vessels, ample pedicle, and ability to be grafted on either side. Furthermore, this highly vascular tissue is available in surprisingly large quantities, and its donor scar is hidden in the hair. The authors have found this flap useful (1) in covering exposed bone and tendon without adding unwanted bulk, (2) in providing thin flap coverage or lining in major facial reconstruction, (3) in covering vital structures such as exposed nerves and vessels, (4) in providing neovascularity both as a recipient graft bed and for control of chronic infection, and (5) in reestablishing gliding-tendon mechanisms. The authors have successfully employed this free flap in 15 cases which involved deformities of the ankle, foot, Achilles tendon, forearm, hand, nose, and contralateral ear and scalp. Seven cases are utilized to illustrate the broad application of this unique and versatile free flap.

Free perichondrial graft from the ear to the knee in rabbits

Perichondrial grafts used in arthroplasties have been placed routinely with the cartilage-producing surface facing the joint space. Our study evaluates whether the orientation of the cartilage-producing surface of the perichondrial graft toward or away from the eburnated bone had any effect on the graft pattern 8 weeks after surgery. Fourteen rabbits were studied. The cartilage of both lower limb patellae was removed in all rabbits. The eburnated surfaces of 12 rabbits received perichondrial grafts from the ear, cartilage-producing side facing the joint space in one limb and cartilage-producing surface facing the bone in the other. Two rabbits that received no perichondrial grafts were also studied. After 8 weeks, the animals were killed and the patellar surfaces evaluated by gross and histologic studies. We observed that graft orientation made no difference in the histologic appearance or the thickness of the neocartilage formed.

Secondary ear reconstruction with cartilage grafts covered by axial, random, and free flaps of temporoparietal fascia

Secondary ear reconstructions due to either previous surgical failures or severe traumatic injuries present a significant reconstructive challenge. In this paper we introduce an aggressive reconstructive approach in which radical scar excision is followed by immediate coverage of a newly sculpted cartilage framework with a temporoparietal fascial flap and skin graft. This approach evolved through experience with 40 patients who required secondary reconstructions due to either previous surgeries or trauma.

The correction of microtia with autogenous cartilage grafts: II. Atypical and complex deformities

Microtia encompasses a diverse variety of derformities whose correction must be considered individually. In part I, the classic form of microtia is described. In this article, an overview of complex microtic problems is presented and various techniques to facilitate their management are proposed.

The correction of mi-rotia with autogenous cartilage grafts: I. The classic deformity.?

Microtia encompasses a variety of deformities whose correction presents a considerable technical challenge. In this paper, practical techniques are presented that facilitate the management of the classic form of microtia. This approach was formulated through experience with 76 patients.

Nipple-areola reconstruction following mastectomy: an alternative to the use of labial and contralateral nipple-areolar tissues

The techniques described herein were developed to recreate a nipple-areolar complex that avoids the inherent disadvantages of labial and "nipple-sharing" techniques. We have presented a practical, reliable, one-stage method that utilizes other tissues, and has evolved through experience with 14 cases.

Replantation of amputated distal phalangeal parts of fingers without vascular anastomoses, using subcutaneous pockets

Subcutaneous "pocketing" is proposed as a simple and convenient method to nourish a denuded, replanted end of a finger, when the amputation is between the lunule and the DIP joint. The investigation of a laboratory model is presented, and our initial clinical experience is reported.

The role of pressure therapy in management of earlobe keloids: preliminary report of a controlled study

Prevention of postexcisional recurrence of the common earlobe keloid has long been an enigma to the surgeon. The increased realization that pressure aids in diminishing hypertrophic burn scars has stimulated us to develop an effective pressure device to control the collagen overgrowth frequently occurring after initial keloid excision. Our device is a decorative spring-pressure earring that is applied to the earlobe 2 weeks after excision of the keloid. The patient is instructed to wear the earring for 4 to 6 months. An effective evaluation of this device was carried out through its bilateral use in some patients. The earring was used initially on only 1 ear; when early recurrence was detected in the control ear, application of the device diminished and prevented keloid reformation. This innovation promises to be an important adjunct in the prevention of postexcisional recurrence of earlobe keloids, and the preliminary results are reported with a 12 to 15 month follow-up. Constant light pressure is discussed as an effective means of preventing postexcisional recurrence of these lesions.

Reconstruction of traumatic ear deformities

Post-traumatic auricular deformity is a unique and varied problem that taxes the ingenuity of the plastic surgeon. Case individualization is repeatedly demanded and a systematic assessment of the residual tissue is requisite to planning an appropriate reconstruction. A basic guideline is presented to emphasize fundamental principles of plastic surgery and tissue transplantation as they are applied to this challenging area of our specialty.

Perichondro-cutaneous graft

A perichondro-cutaneous graft uniquely provides skin cover with the potential of generating its own cartilaginous support. An initial laboratory investigation is reported, and various applications of this graft to reconstructive facial surgery are proposed. Several clinical cases are presented.

Nipple-areola reconstruction with auricular tissues

Various methods of reconstructing the nipple-areolar complex with auricular tissues are presented. A basic one-stage reconstructive technique is described which seems suitable for the use of various tissues. An alternative method of correcting the inverted nipple is reported.

The acquired auricular deformity. A systematic approach to its analysis and reconstruction

Acquired ear deformities present unique and varied problems which tax the ingenuity of the plastic surgeon. Case individualization is necessary, and a systematic assessment of the residual tissues is a requisite when planning an appropriate reconstruction. Cases performed by one surgeon have been used to demonstrate the basic principles of these repairs. A systematic approach to the reconstruction of these acquired deformities is presented.

Reconstruction of ear, eyebrow, and sideburn in the burned patient

Some new variations are described for partial and total ear reconstructions, eyebrow reconstructions, and sideburn reconstructions in burned patients.