Reinfección por SARS-CoV-2 en pacientes con antecedentes de MIS-C. Presentación de dos casos / MIS-C patients who were reinfected with SARS-CoV-2. Report of 2 cases

El síndrome inflamatorio multisistémico pediátrico (MIS-C, por su sigla en inglés) es una enfermedad rara. Se desconoce si los niños que se recuperaron del MIS-C tienen riesgo de recurrencia de MIS-C cuando presentan reinfección por SARS-CoV-2. El objetivo de este estudio es describir los casos de dos niñas que se recuperaron del MIS-C y presentaron reinfección por SARS-CoV-2 sin recurrencia de MIS-C.

Multisystem inflammatory syndrome in children (MIS-C) is a rare condition. It is still unknown if children who have recovered from MIS-C are at a risk of recurrence of MIS-C when they are reinfected with SARS-CoV-2. In this study, we aimed to report 2 children who recovered from MIS-C and reinfected with SARS-CoV-2 without recurrence of MIS-C.

Comparison of humoral immune response in heterologous and homologous COVID-19 booster vaccine groups using CoronaVac and mRNA-based BNT162b2 vaccines.

BACKGROUND: Heterologous COVID-19 booster vaccination is an alternative strategy to homologous vaccination, especially in developing countries, due to shortages, delays, or unequal distribution of COVID-19 vaccines. We compared cohorts vaccinated with different vaccine combinations to investigate whether a heterologous booster dose of mRNA-based BNT162b2 vaccine boosts the immune response in individuals primed with the CoronaVac vaccine. METHODS: Anti-RBD IgG is generally measured 4 weeks after primary immunization and 4 weeks after booster vaccination. Data on anti-receptor-binding domain (anti-RBD) IgG antibody titers and clinical characteristics were provided by infection control units. RESULTS: The highest median anti-RBD IgG antibody titers (14589 AU/mL) after primary immunization was observed in the group vaccinated with two doses of BNT162b2 vaccine. Antibody titers were lower 4 months or more after the second CoronaVac vaccine dose in CoronaVac recipients with or without previous COVID-19. In the homologous COVID-19 booster vaccine group (primed with two doses of CoronaVac 4 weeks apart and a single booster dose of CoronaVac) the median anti-RBD titers decreased from 1025 to 242 AU/mL before the booster dose. In the heterologous group (primed with two doses of CoronaVac 4 weeks apart and a single booster dose of BNT162b2), the median anti-RBD titer increased to 31624 AU/mL, a 132-fold increase, 16 days after the booster dose. CONCLUSIONS: After the second dose of CoronaVac, protective neutralizing antibody levels decrease over time, and a booster dose is required. Heterologous COVID-19 booster vaccination with BNT162b2 is effective at boosting neutralizing antibody levels.

MIS-C patients who were reinfected with SARS-CoV-2. Report of 2 cases. / Reinfección por SARS-CoV-2 en pacientes con antecedentes de MIS-C. Presentación de dos casos.

Multisystem inflammatory syndrome in children (MIS-C) is a rare condition. It is still unknown if children who have recovered from MIS-C are at a risk of recurrence of MIS-C when they are reinfected with SARSCoV-2. In this study, we aimed to report 2 children who recovered from MIS-C and reinfected with SARSCoV-2 without recurrence of MIS-C.

El síndrome inflamatorio multisistémico pediátrico (MIS-C, por su sigla en inglés) es una enfermedad rara. Se desconoce si los niños que se recuperaron del MIS-C tienen riesgo de recurrencia de MIS-C cuando presentan reinfección por SARS-CoV-2. El objetivo de este estudio es describir los casos de dos niñas que se recuperaron del MIS-C y presentaron reinfección por SARS-CoV-2 sin recurrencia de MIS-C.

The Epidemiology of Influenza Virus Infection and Group A Streptococcal Pharyngitis in Children Between 2011 and 2018 in an Outpatient Pediatric Clinic.

Background The frequency of influenza virus infections and group A beta-hemolytic streptococcus (GAS) pharyngitis varies according to populations. We aimed to investigate the frequency of influenza virus and streptococcal pharyngitis infections in a pediatric outpatient cohort with many pediatric admissions in Istanbul. Materials and methods Children with upper respiratory tract infection (URTI) symptoms between 2011 and 2018 who underwent rapid diagnostic tests for influenza virus or streptococcal infection were evaluated retrospectively. Results The total number of pediatric cases admitted between 2011 and 2018 was 185,228, of which 119,928 were under five years old and 66,300 were children over five years old. The mean frequency of the influenza virus was 1,283 per 100,000 children, and the mean frequency of streptococcal pharyngitis was 1,764 per 100,000 children. The frequency of influenza has increased over the years. The frequency of streptococcal infection is higher in children over five years of age, and its frequency has decreased in this group. Conclusions The frequency of influenza virus infection and GAS pharyngitis varies according to years and seasons. Winter and spring were the seasons with the most frequent positive influenza virus and GAS pharyngitis. Although influenza frequency increased annually, this phenomenon was not observed in the frequency of GAS pharyngitis.

Comparison of humoral immune response in heterologous and homologous COVID-19 booster vaccine groups using CoronaVac and mRNA-based BNT162b2 vaccines

ABSTRACT Background: Heterologous COVID-19 booster vaccination is an alternative strategy to homologous vaccination, especially in developing countries, due to shortages, delays, or unequal distribution of COVID-19 vaccines. We compared cohorts vaccinated with different vaccine combinations to investigate whether a heterologous booster dose of mRNA-based BNT162b2 vaccine boosts the immune response in individuals primed with the CoronaVac vaccine. Methods: Anti-RBD IgG is generally measured 4 weeks after primary immunization and 4 weeks after booster vaccination. Data on anti-receptor-binding domain (anti-RBD) IgG antibody titers and clinical characteristics were provided by infection control units. Results: The highest median anti-RBD IgG antibody titers (14589 AU/mL) after primary immunization was observed in the group vaccinated with two doses of BNT162b2 vaccine. Antibody titers were lower 4 months or more after the second CoronaVac vaccine dose in CoronaVac recipients with or without previous COVID-19. In the homologous COVID-19 booster vaccine group (primed with two doses of CoronaVac 4 weeks apart and a single booster dose of CoronaVac) the median anti-RBD titers decreased from 1025 to 242 AU/mL before the booster dose. In the heterologous group (primed with two doses of CoronaVac 4 weeks apart and a single booster dose of BNT162b2), the median anti-RBD titer increased to 31624 AU/mL, a 132-fold increase, 16 days after the booster dose. Conclusions: After the second dose of CoronaVac, protective neutralizing antibody levels decrease over time, and a booster dose is required. Heterologous COVID-19 booster vaccination with BNT162b2 is effective at boosting neutralizing antibody levels.

Comparison of immunogenicity and reactogenicity of inactivated SARS-CoV-2 vaccine (CoronaVac) in previously SARS-CoV-2 infected and uninfected health care workers.

The effects of inactivated SARS-CoV-2 vaccine (CoronaVac) on previously naturally infected individuals are unknown. This study compared immunogenicity and reactogenicity of CoronaVac in once naturally infected health-care workers (HCWs) and uninfected HCWs. All HCWs were immunized with two doses of CoronaVac (600 U/0.5 ml) intramuscularly at a 28-day interval. Adverse reactions were obtained by web-based questionnaires or telephone calls seven days after each vaccine dose. Detection of antibody levels against the receptor-binding domain (RBD) of SARS-CoV-2 spike protein was done four weeks after the second dose of the vaccine. We enrolled 103 previously naturally infected and 627 uninfected HCWs. The mean time for vaccination after the first nasopharyngeal SARS-CoV-2 positivity was 64 days (range: 15-136 days) in previously naturally infected HCWs. Among the previously naturally infected HCWs, 41 (40%) were asymptomatic, 52 (50%) had mild upper respiratory tract infections, 10 (105) had pneumonia, and only 6 (5%) were hospitalized. Any reported adverse reactions, either from the first dose or the second dose of vaccine administration, did not differ between previously infected and uninfected HCWs. Anti-RBD antibody titers were obtained in 50 (51%) of 103 previously infected HCWs and 142 (23%) of 627 uninfected HCWs. Anti-RBD antibody titers were significantly higher in HCWs with a previous natural infection (median 1220 AU/ml, range: 202-10328 AU/mL) than in uninfected HCWs (median: 913 AU/ml, range: 2.8-15547 AU/mL, p = .032). CoronaVac administration was safe and may elicit higher antibody responses in previously naturally infected individuals.

Cord blood antibody following maternal SARS-CoV-2 inactive vaccine (CoronaVac) administration during the pregnancy.

Maternal vaccination with SARS-CoV-2 vaccines has not been well studied yet in terms of safety and efficacy for protecting the newborn by the placental passage of antibodies. We reported 34 years of old health care worker (HCW) without any known SARS-CoV-2 infection. She had the first dose of SARS-CoV-2 inactivated virus vaccine (CoronaVac, Sinovac Life Science Co, Ltd, Beijing, China) at a gestational age of 28 weeks. The second dose of vaccine was given four weeks later at a gestational age of 32 weeks. HCW did not report any vaccine-related adverse events after either the first or second dose of the vaccine. Three weeks after the second dose of the vaccine, her anti-receptor-binding domain (RBD) of SARS-CoV-2 spike protein antibody was 779 arbitrary units (AU) per ml. She gave a birth of 38 weeks three days gestation age of healthy, full-term girl with a birth weight of 2770 gr. The mother's anti-RBD antibody was 734 AU/ml, the infant's cord blood anti-RBD antibody level was 764 AU/ml, respectively, cord sera/maternal sera transfer ratio was 1,04. This infant is the first identified case of SARS-CoV-2 IgG antibodies detectable in cord blood after maternal vaccination with CoronaVac.

Nontypeable Haemophilus influenzae Otitis Media: Mastoiditis and Meningitis Complicated with Central Venous Thrombosis in an Immunocompetent Child.

Implementation of the Haemophilus influenzae type B (Hib) conjugate vaccine brought about a reduction in the number of cases and morbidity from type B but an increase in nontypeable strain infections. Nontypeable Haemophilus influenzae (NTHi) commonly colonizes children's upper respiratory tract and causes otitis media, sinusitis, and bronchitis. Invasive NTHi diseases, such as meningitis and septicemia, have rarely been reported. Herein, we discuss a previously healthy, fully immunized 3-year-old girl presented with otitis media and mastoiditis leading to meningitis caused by NTHi complicated with central venous thrombosis. She was treated with antibiotics, mastoidectomy and ventilation tube insertion, and anticoagulation therapy and recovered uneventfully. Through this case, we wish to share our unique clinical experience that NTHi should be born in mind as a potential pathogen that can cause meningitis in previously healthy children, which may be helpful in future cases.

Pediatricians' COVID-19 experiences and views on the willingness to receive COVID-19 vaccines: a cross-sectional survey in Turkey.

Developing an effective and safe vaccine against Covid-19 will facilitate return to normal. Due to hesitation toward the vaccine, it is crucial to explore the acceptability of the COVID-19 vaccine to the public and healthcare workers. In this cross-sectional survey, we invited 2251 pediatricians and 506 (22%) of them responded survey and 424 (84%) gave either nasopharyngeal swap or antibody assay for COVID-19 and 71 (14%) of them got diagnosis of COVID-19. If the effective and safe COVID-19 vaccine was launched on market, 420 (83%) of pediatrician accepted to get vaccine shot, 422 (83%) of them recommended vaccination to their family members, 380 (75%) of them accepted to vaccine their children and 445 (85%) of them offered vaccination to their pediatric patients. Among the participated pediatricians 304 (60%) of them thought COVID-19 vaccine should be mandatory. We found that there are high COVID-19 vaccine willingness rates for pediatricians for themselves, their own children, family members and their pediatric patients. We also found that being a pediatric subspecialist, believing in achieving an effective vaccine, willingness to participate in the phase 1-2 clinical vaccine trial, willingness to get an influenza shot this season, believing a vaccine and vaccine passport should be mandatory were significant factors in accepting the vaccine. It is important to share all information about COVID-19 vaccines, especially effectiveness and safety, with the public in a clear communication and transparency. The opposite will contribute to vaccine hesitancy and anti-vaccine movement.

Symptomatic recurrence of SARS-CoV-2 infection in healthcare workers recovered from COVID-19.

There is rising concern that patients who recover from COVID-19 may be at risk of recurrence. Increased rates of infection and recurrence in healthcare workers could cause the healthcare system collapse and a further worsening of the COVID-19 pandemic. Herein, we reported the clinically symptomatic recurrent COVID-19 cases in the two healthcare workers who treated and recovered from symptomatic and laboratory confirmed COVID-19. We discuss important questions in the COVID-19 pandemic waiting to be answered, such as the protection period of the acquired immunity, the severity of recurrence and how long after the first infection occurs. We aimed to emphasize that healthcare workers should continue to pay maximum attention to the measures without compromising.

Cost and length of hospital stay for healthcare facilityonset Clostridioides Difficile infection in pediatric wards: a prospective cohort analysis.

BACKGROUND: Clostridioides difficile (C. difficile) is a well-known causative agent of healthcare associated infection, it increases medical cost besides increasing morbidity and mortality. This study was conducted to determine the incidence, and economic burden of healthcare facility-onset C. difficile infection (HO-CDI) in children. METHODS: Data was acquired with a prospective cohort study conducted in pediatric wards of a tertiary university hospital between August 2015 to August 2016. The HO-CDI was defined as diarrhea that began after 48 hours of admission with a positive cytotoxic stool assay for the presence of toxin A and/or B of C. difficile. RESULTS: In the 3172 admissions in one year, 212 (7%) healthcare associated diarrhea (HAD) episodes were observed, in 25 (12%) of them C. difficile was identified in which 6 (25%) cases < 2-year-old. The incidence of HOCDI was estimated as 8.8/10,000 patient-days. Cases with HO-CDI (n=19) were compared with cases with non- CDI-HAD (n=102); the presence of one of the risk factors for CDI increased the risk for HO-CDI (5,05; 95% Cl: 1.10-23.05; P 0,037), the median length of stay (LOS) attributable HO-CDI was 7 days (IQR,5-10) per admission, whereas for non-CDI-HAD was 2 days (IQR,0-4) (p=0.036). General hospitalization costs in the two groups were similar, specifically estimated costs attributable to HO-CDI and non-CID-HAD were $294.0 and $137.0 per hospitalization respectively (p= < 0.0001). CONCLUSION: Although in children the incidence of HO-CDI is increasing, its clinical manifestation is still milder and effective infection control measures with antibiotic stewardship can limit related morbidly, mortality, LOS, and cost.

Reduction of nosocomial infections in the intensive care unit using an electronic hand hygiene compliance monitoring system.

INTRODUCTION: Healthcare-associated infection is an important cause of mortality and morbidity worldwide. Well-regulated infection control and hand hygiene are the most effective methods for preventing healthcare-associated infections. This study evaluated and compared conventional hand hygiene observation and an electronic hand-hygiene recording and reminder system for preventing healthcare-associated infections. METHODOLOGY: This pre- and post-intervention study, employed an electronic hand-hygiene recording and reminder system for preventing healthcare-associated infections at a tertiary referral center. Healthcare-associated infection surveillance was recorded in an anesthesia and reanimation intensive care unit from April 2016 to August 2016. Hand-hygiene compliance was observed by conventional observation and an electronic recording and reminder system in two consecutive 2-month periods. healthcare-associated infections were calculated as incidence rate ratios. RESULTS: The rate of healthcare-associated infections in the electronic hand- hygiene recording and reminder system period was significantly decreased compared with that in the conventional hand-hygiene observation period (incidence rate ratio = 0.58; 95% confident interval = 0.33-0.98). Additionally, the rate of central line-associated bloodstream infections and the rate of ventilator-associated pneumonia were lower during the electronic hand hygiene recording and reminder system period (incidence rate ratio= 0.41; 95% confident interval = 0.11-1.30 and incidence rate ratio = 0.67; 95% confident interval = 0.30-1.45, respectively). CONCLUSIONS: After implementing the electronic hand hygiene recording and reminder system, we observed a significant decrease in healthcare-associated infections and invasive device-associated infections. These results were encouraging and suggested that electronic hand hygiene reminder and recording systems may reduce some types of healthcare-associated infections in healthcare settings.

Comparison of Clinical and Laboratory Features and Treatment Options of 237 Symptomatic and Asymptomatic Children Infected with SARS-CoV-2 in the Early Phase of the COVID-19 Pandemic in Turkey.

Little is known about the therapeutic use of hydroxychloroquine in pediatric patients with coronavirus disease 2019 (COVID-19). Here, we retrospectively retrieved data of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) PCR-positive pediatric patients from 20 hospitals in 8 Turkish cities. We obtained epidemiological, clinical, and laboratory features of the patients, as well as the drugs used for treating COVID-19. A total of 237 nasopharyngeal swab SARS-CoV-2 PCR-positive children were included in the study from March 26, 2020 to June 20, 2020. The mean age of asymptomatic children (118 ± 62 months) was higher than that of symptomatic children (89 ± 69 months). Symptomatic children had significantly lower mean lymphocyte counts and higher mean CRP, D-dimer, procalcitonin, and LDH levels than asymptomatic children in the univariate analysis. Among 156 children, 78 (50%), 15, 44, and 21 were treated with a hydroxychloroquine-containing regimen, hydroxychloroquine + azithromycin + oseltamivir, hydroxychloroquine + azithromycin, and hydroxychloroquine alone, respectively. Among 156 patients who received medical treatment, 90 (58%) underwent pre- and/or post-treatment electrocardiogram (ECG). However, none of them had ECG abnormalities or required hydroxychloroquine discontinuation due to adverse drug reactions.

Impact of self-financed rotavirus vaccination on acute gastroenteritis in young children in Turkey.

Rotavirus (RV) vaccines have been available in Turkey since 2006. These vaccines are not funded by the National Health System, so consequently their coverage rate in children has reached only 13-18%. We conducted a retrospective record review including all children ≤60 months of age presenting to study hospitals with suspected or clinical acute gastroenteritis (AGE) between 2012 and 2018. During the study, 109,605 children ≤60 months of age were admitted to pediatric out-patient clinics and pediatric emergency room, of which 15,501 (14%) were diagnosed with AGE. Incidence of RV-positive AGE decreased from 4.47 per 1,000 children in 2012 to 2.48 per 1,000 in 2018. A total of 4,805 (31%) such children were hospitalized with RV-positive AGE, a decrease from 1.9 per 1,000 children in 2012 to 0,45 per 1,000 in 2018. The length of hospital stays (LOS) of RV-positive AGE was 2.47 ± 1.15 days compared to LOS of RV-negative AGE 1.59 ± 1.17 days (p < .001). The overall cost of RV-positive AGE ($335 ± 200) was higher than that for RV-negative AGE ($280 ± 148) cases (p = .015). Vaccine effectiveness against any case of RV-positive AGE was 75,1% (95% CI: 65-86%). Despite the low level of vaccine coverage, the introduction of RV vaccination had a positive impact on the incidence of RV-positive AGE and related hospitalizations in young children.

Incidence of varicella and herpes zoster after inclusion of varicella vaccine in national immunization schedule in Turkey: time trend study.

The aim of the study was to investigate changes in the incidences of Varicella and Herpes Zoster (HZ) following introduction of single dose Varicella vaccine (VV) in Turkey. Changes in the incidences of varicella and HZ per 100,000 population were compared with pre (2011-2012) and post-VV period (2018-2019) throughout years between years 2011 and 2019 both for children and adults. In children ≤5 years of age, the annual incidences of varicella significantly decreased from 290 per 100000 children in 2011 to 24 per 100000 children in 2019 [p = .0001]. Also, for children ≤5 years the mean annual incidence of varicella decreased significantly [326/100000 ±51/100000 vs 23/100000 ± 1/100000; p = .014] between pre- and post-VV period. Moreover, the annual incidences of varicella significantly decreased from 43 per 100000 children in 2011 to 26 per 100000 children in 2019 in children age between 6 and 17 years. On the other hand, incidence of varicella in adult population (age >17 years) did not change significantly. Besides, the annual incidences of Herpes Zoster did not change significantly in children age stratas but significant increment observed in adult population. This increment was significant in adult age strata of 18-44 years, but non-significant in age strata of 45-64 years and >64 years. Thus, our study showed a significant reduction in the incidences of Varicella in children age stratas whereas significant increment in the incidence of HZ in adult population after the implementation of VV into the NIP of Turkey.

The Use of Social Network in Daily Pediatric Practice and Education: Turkish Pediatric Atelier.

Using social media applications in pediatric education is not outdated, and its effectiveness has not been tested yet. For this reason, we shared the first results of the Pediatric Atelier experience that we realized through telegram application. We make an online survey to investigate the needs, requirements, pleasure, and suggestions of members through a web-based questionnaire. This cross-sectional survey study was delivered only to participants who were members of the workshop via their email addresses. Online questionnaires organized using Google Forms were sent to pediatric workshop members between March and June 2019. The questionnaire consisted of questions that measured the participants' basic demographic data, the use of the workshop, and the overall impact of the workshop on their professional behavior. While the institutions and positions of the participants were recorded, no other personal data (such as address and telephone) were collected. Among the 997 members, 417 (42%) of them answered the questionnaire. Respondents included 300 (72%) pediatrician, 21 (5%) pediatric subspeciality fellows, and 75 (18%) pediatric subspecialists. Of the 417 respondents, 217 (52%) were working in Istanbul, and 200 (48%) were working in other cities of Turkey. Among the responders, 233 (56%) were working in private hospitals or doctor offices. A total of 520 cases were consulted in 241 days of study period. Most consultations (n = 309, %59) were made from the Istanbul metropolitan area, and 203 (40%) consultations were from other cities of Turkey. The most frequently consulted departments were Pediatric infectious diseases: 166 (32%), Pediatric hematology and oncology: 56 (11%), and Neonatology: 43 (8%). Of the 520 consulted cases, 44 (8%) were related to life-threatening events, and 25 of them were hospitalized in the intensive care units, and 6 of them were required surgical operations. Of the 94% of responders thought this platform was useful and 82% of them stated that the case counseling part of the atelier was the most useful part. We think that the development of technology and artificial intelligence may lead to the usage of on-line platforms or systems in clinical medical practice. Clinical Trial Registration (if any). Registry name, registration number, web link to study on registry, and data sharing statement.

Response to "Letter to the Editor: Vaccine Failures in Pediatric Cases Caused by Streptococcus pneumoniae Serotype 19A".

We are happy to answer to the Letter from Ozkaya-Parlakay et al. to the Editor commenting on our recent paper, 1  investigated impact of the 13-valent pneumococcal conjugate vaccine (PCV13)  on the incidences of community-acquired pneumonia and pneumonia-related hospitalizations in children ≤5 years after its implementation into the national immunization program (NIP) of Turkey.   Ozkaya-Parlakay et al. draw attention to vaccine failure and importance of continuous  surveillance of relevant disease especially in the perspective of  Streptococcus pneumoniae  serotype 19A. They supported their opinion by their clinical observation of seven children who were vaccinated with PCV13 developed empyema and meningitidis caused by Streptococcus pneumoniae  serotype 19A 
 in Turkey.

Impact of the 13-valent pneumococcal conjugate vaccine on the incidences of community-acquired pneumonia and pneumonia-related hospitalizations in children ≤5 years after its implementation into the national immunization program of Turkey.

The aim of the study was to investigate changes in the incidences of community-acquired pneumonia (CAP) and CAP-related hospitalizations following introduction of 13-valent pneumococcal conjugate vaccine (PCV13) in children ≤5 years of age into the national immunization programme (NIP) of Turkey. PCV7 was included in the NIP of Turkey in November 2008 and was replaced by PCV13 in late 2011. Changes in the incidences of CAP and CAP-related hospitalizations per 100,000 children admissions were investigated from 2011 to 2017. A total of 225,963 children visits were recorded; CAP was diagnosed in 4863 (2.15%) children and 1086 (22%) of them hospitalized between 2011 and 2017. The incidence of CAP declined from 5448 to 1144/100,000 from 2011 to 2017 (p = .001, r = -0.965). When the mean annual incidence of CAP between the transition period of PCV13 (2011/2012) was compared with a post-PCV13 period (2016/2017), CAP incidence was found to be 22% lower (p = .009). Also, the incidence of CAP-related hospitalization decreased significantly from 943 to 335/100,000 from 2011 to 2017 (p = .004 r = -0.91). Moreover, the mean incidence of CAP hospitalization declined 35% (p = .01) between the transition period of PCV13 and a post-PCV13 period. Thus, our study showed a significant reductions in the incidences of CAP and CAP-related hospitalization in children ≤5 years-old after the implementation of PCV13 into the NIP of Turkey.

Impact of the 13-valent pneumococcal conjugate vaccine on the incidences of acute otitis media, recurrent otitis media and tympanostomy tube insertion in children after its implementation into the national immunization program in Turkey.

The aim of this study was to investigate changes in the incidences of acute otitis media (AOM), recurrent AOM (rAOM) and tympanostomy tube (TT) insertion in children following the introduction of 13-valent pneumococcal conjugate vaccine (PCV13) into the national immunization program (NIP) of Turkey in April 2011. National coverage for the PCV7 was 97% in 2009, 93% in 2010, 96% in 2011 and for the PVC13 was 97% in 2012, 97% in 2013, 96% in 2014, 97% in 2015, 98% in 2016, and 96% in 2017 for Turkish children younger than 12 months of age. A total of 499932 pediatric visits were recorded, and AOM was diagnosed in 23005 (4.6%) children. The incidence of AOM in children ≤5 years of age decreased from 10700/100000 (2011) to 4712/100000 (2017), with a significant decreasing trend (p < .001, r = -0.965). When the mean annual incidences of AOM between the transition period of PCV13 (years 2011/2012) were compared with those of a post-PCV13 period (years 2016/2017) for children ≤5 years of age, the incidence of AOM was found to be decreased by 54% (p = 0.013). The mean incidence of TT insertion was found to be decreased by 65% (p = 0.003) between the transition period of PCV13 and a post-PCV13 period for children ≤5 years of age. On the other hand, rAOM incidence was found to be increased in whole pediatric age groups. Our study showed a significant decrease in the incidences of AOM and TT insertion in children ≤5 years old after implementation of PCV13 in the NIP in Turkey.

The impact of vitamin B12 deficiency on infant gut microbiota.

Although physiologic and neurologic consequences of micronutrient deficiencies have been addressed extensively, less is known about their impact on developing gut microbiota. Vitamin B12 deficiency is a common micronutrient deficiency in infants. We aimed to analyze the gut microbial composition of exclusively breastfed infants aged between 4 and 6 months with and without vitamin B12 deficiency by 16S rRNA gene sequencing. In a subgroup of infants with vitamin B12 deficiency, stool samples are recollected and reanalyzed after vitamin B12 supplementation. A total of 88 infants' stool samples (median age 4 months [IQR 4-5], 50% males) were analyzed, of which 28 (31.8%) were vitamin B12 sufficient and 60 (68.2%) were vitamin B12 insufficient. Comparisons between vitamin B12-sufficient and vitamin B12-insufficient infants revealed no evidence of differences in the microbiota. Proteobacteria, Firmicutes, Actinobacteria, and Bacteroidetes were the most abundant phyla in all groups. There was no difference between the pre- and post-treatment composition of gut microbiota.Conclusion: Vitamin B12-deficient infants have similar gut microbial composition as vitamin B12-sufficient infants. Since the samples were collected at an early period of life and the exposure to deficiency was relatively short, it may be possible that the effects were not fully established.What is Known: • Vitamin B12 is an essential vitamin for humans and also a crucial compound for human gut microbiota. • Vitamin B12 deficiency is common in exclusively breastfed infants. • In contrast to the adult gut microbiota, infant gut microbiota has been shown to have decreased capacity for de novo synthesis of vitamin B12 and depend on dietary source of vitamin B12.What is New: • There is no difference in the gut microbial composition of vitamin B12-deficient and vitamin B12-sufficient infants.