The prevalence of hepatitis C virus (HCV) antibody in newborn infants in 3 counties in southern California in 2003 was found to be 2.5 per 1000 live births using dried blood spot testing. With advances in HCV antiviral therapy providing decreasing morbidity from chronic HCV infection, prenatal HCV screening to identify both mothers and at-risk infants should be reconsidered.

The California Genetic Disease Screening Program (GDSP) employs a fixed immunoreactive trypsinogen (IRT) cutoff followed by molecular testing to screen newborns for cystic fibrosis (CF). The cutoffs approximate a 1.6% yearly IRT screen-positive rate; however, seasonal variation in IRT population means has led us to develop a model to establish fixed IRT cutoffs that anticipate seasonal variation and minimize missed cases below cutoff. We utilized an ARIMA model to fit monthly IRT screen-positive percentiles and estimated regular seasonal expectations. We established a retrospective cohort followed for at least 1.5 years to capture missed false-negative CF cases. We compared missed CF cases identified by seasonal cutoffs vs. floating cutoffs. GDSP screened 7,410,003 newborns, from July 2007 to December 2022, and missed 36 CF cases below the fixed cutoff; five of the 36 were within 3 ng/mL below the cutoff. There was a regular, seasonal cycle that varied from 1.4% in summer to 1.8% in winter. We would have missed 59 CF cases using a 1.6% daily floating cutoff. California would need to use a 4% daily floating cutoff to improve our current detection rate, which would double the number of specimens sent for costly molecular analysis.

The original article to which this Erratum refers was published in Human Mutation 24:353 Human Mutation(2004) 24(4) 353 In the original published version of this article, the novel CFTR gene mutation 2289_2295del7bpinsGT (c.2157_ 2163del7insGT) (p. Leu719fs) should have been characterized as 2289_2298del10ins5GTAAG (c.2157-2166del10ins5GTAAG) (p.Leu719fs). This error is found in several places in the pdf version of the article: Page 3 – line 45 (Results, line 5); Page 4 – (Table 1a, line 6); Page 6 – line 52; Page 9 – (Table 2B, patient #11, line 3). In addition, the twins reported in Table 1B as carrying the rare CFTR mutation 2184insA were in fact siblings with the novel 1285_1288dupTA mutation. This error affects the following: Page 1 – Abstract, line 11 (“20 distinct rare mutations”); Page 4 – Results, line 9 (“8 times including 1 sibling pair and 1 homozygote”); Page 4 – Table 1A, line 5, column 6 (“8 (1 sib; 1 homo)”); Page 5 – Table 1B (remove line 9 starting with “2184insA”); Page 6 – Clinical Correlation, line 12 (“six unrelated patients”); Page 10 – Discussion, line 6 (“6 unrelated individuals”); Page 10 – line 10 (“66 CFTR alleles”); Page 10 – line 24 (“76 distinct mutations, including 28 discovered by TTGE…”). The authors apologize for these errors.

The California Genetic Disease Screening Program (GDSP) employs a fixed immunoreactive trypsinogen (IRT) cutoff followed by molecular testing to screen newborns for Cystic Fibrosis (CF). The cutoffs approximate a 1.6% yearly IRT screen positive rate, however seasonal variation in IRT population means led us to develop a model to establish fixed IRT cutoffs that anticipate seasonal variation and minimize missed cases below cutoff. We utilized an ARIMA model to fit monthly IRT screen-positive percentiles and estimated regular seasonal expectations. We established a retrospective cohort followed for at least 1.5 years to capture missed false negative CF cases. We compared missed CF cases identified by seasonal cutoffs vs floating cutoffs. GDSP screened 7,410,016 newborns, from July 2007 to Dec. 2022, and missed 36 CF cases below the fixed cutoff; five of the 36 were within 3 ng/mL below the cutoff. There was a regular, seasonal cycle that varied from 1.4% in summer to 1.8% in winter. We would have missed 59 CF cases using a 1.6% daily floating cutoff. California would need to use a 4% daily floating cutoff to improve our current detection rate which would double the number of specimens sent for costly molecular analysis.

To investigate COVID-19 surveillance among pregnant women, the California Genetic Disease Screening Program conducted a screening performance and seroprevalence evaluation of maternal SARS-CoV-2 antibodies detected in banked newborn dried blood spots (DBS). We obtained seropositive results for 2890 newborn DBS from cohorts in 2020 and 2021 using Enable Bioscience’s Antibody Detection by Agglutination-PCR (ADAP) assay for SARS-CoV-2 antibodies. To infer maternal infection, we linked 312 women with a known laboratory-confirmed COVID-19 episode with their newborn’s DBS SARS-CoV-2 antibody result. Among 2890 newborns, we detected 453 (15.7%) with SARS-CoV-2 antibodies in their DBS. Monthly snapshot statewide seroprevalence among neonates was 12.2% (95% CI 10.3–14.1%, n =1156) in December 2020 and 33.3% (95% CI 29.1–37.4%, n = 26) in March 2021. The longest time recorded from COVID-19 infection to a seropositive neonatal result was 11.7 months among the 312 mothers who had an available SARS-CoV-2 PCR test result. Approximately 94% (153/163) of DBS were seropositive when a known maternal infection occurred earlier than 19 days before birth. The estimated relative sensitivity of DBS to identify prevalent maternal infection was 85.1%, specificity 98.5% and PPV 99.2% (n = 312); the sensitivity was lowest during the December 2021 surge when many infections occurred within 19 days of birth. Fifty pre-pandemic specimens (100% seronegative) and 23 twin-pair results (100% concordant) support an intrinsic specificity and PPV of ADAP approaching 100%. Maternal infection surveillance is limited by a time lag prior to delivery, especially during pandemic surges.