Vaccination against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been acknowledged as an effective mean of preventing infection and hospitalization.However, the emergence of highly transmissible SARS-CoV-2 variants of concern (VOCs) has led to substantial increase in infections among children and adolescents. Vaccineinduced immunity and longevity have not been well defined in this population. Therefore, we aimed to analyze humoral and cellular immune responses against ancestral and SARSCoV-2 variants after two shots of the BNT162b2 vaccine in healthy adolescents. Although vaccination induced a robust increase of spike-specific binding Abs and neutralizing Abs against the ancestral and SARS-CoV-2 variants, the neutralizing activity against the Omicron variant was significantly low. On the contrary, vaccine-induced memory CD4+ T cells exhibited substantial responses against both ancestral and Omicron spike proteins.Notably, CD4+ T cell responses against both ancestral and Omicron strains were preserved at 3 months after two shots of the BNT162b2 vaccine without waning. Polyfunctionality of vaccine-induced memory T cells was also preserved in response to Omicron spike protein.The present findings characterize the protective immunity of vaccination for adolescents in the era of continuous emergence of variants/subvariants.

Intraductal papillary neoplasms of the bile duct (IPNB) leads to malignant transformation and mucin production. Herein, we presented two cases of mucin-producing IPNB with obstructive jaundice who underwent resection of the intrahepatic lesions and bypass hepaticojejunostomy. The first case was a 69 year-old male patient with 5-year follow up for gallstone disease. Imaging studies showed mucin-secreting IPNB mainly in the hepatic segment III bile duct (B3) and multiple intrahepatic duct stones for which, segment III resection, intrahepatic stone removal, end-to-side choledochojejunostomy and B3 hepaticojejunostomy were conducted. The second case was a 74 year-old female patient with 11-year follow up for gallstone disease. Imaging studies showed mucin-producing IPNB with dilatation of the segment IV duct (B4) and mural nodules for which, segment IV resection, partial resection of the diaphragm and central hepaticojejunostomy were conducted. Both patients recovered uneventfully from surgery. These cases highlight that in patients with IPNB, abundant production of highly viscous mucin inducing obstructive jaundice may be associated with malignant transformation.
Bile Ducts ; Bile Ducts, Intrahepatic* ; Cholangiocarcinoma* ; Choledochostomy ; Diaphragm ; Dilatation ; Female ; Follow-Up Studies ; Gallstones ; Humans ; Jaundice ; Jaundice, Obstructive ; Male ; Mucins