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Acquired Laryngotracheal Disease
Published in Raymond W Clarke, Diseases of the Ear, Nose & Throat in Children, 2023
Typically due to Haemophilus influenza B (Hib), this condition was rampant for much of the twentieth century. Widespread implementation of Hib vacci-nation in children has greatly reduced its incidence, but cases still occur occasionally due to vaccine failure, and rarely due to organisms other than Hib, particularly in vulnerable children such as those with compromised immune systems. Children aged between about 2 and 7 years are especially susceptible. They present with a rapidly progressing febrile illness, sore throat and painful swallow. Airway obstruction may not be immediately apparent but can very quickly progress. Settle and calm the child as much as possible and admit them to hospital for urgent observation and treatment. Avoid anything that might precipitate laryngospasm such as over-enthusiastic examination, the tongue depressor or endoscope until you are satisfied that the airway is secured, usually by ET intubation. Commence IV antibiotics and carefully monitor the airway until the swollen oedematous epiglottis and the surrounding structures have returned to normal before considering extubation. This is preferably accomplished in the controlled setting of a PICU.
Acute Laryngeal Infections
Published in John C Watkinson, Raymond W Clarke, Christopher P Aldren, Doris-Eva Bamiou, Raymond W Clarke, Richard M Irving, Haytham Kubba, Shakeel R Saeed, Paediatrics, The Ear, Skull Base, 2018
Routine infant immunization with conjugate Hib vaccine in the UK began in October 1992. Immunization is achieved by three primary doses followed by a late booster. The incidence of invasive Hib infections in children under 5 has fallen dramatically from an incidence of 35.5/100 000 for the year preceding vaccine implementation to 0.06/100 000 in 2012.29 A reduction in the incidence of acute epiglottitis of approximately 90% has been documented in countries in which an immunization programme has been established. In the UK there was a resurgence of cases in 2003 with over 230 cases of Hib infection, causing a booster programme to be launched.30 Vaccine failure does occur but in fewer than 10% of cases is there an identifiable clinical risk factor predisposing to infection. An increasing number of cases may be due to infection with an organism other than Haemophilus and continued vigilance among clinicians is required.27 There is evidence that a longer duration of breastfeeding (more than 13 weeks) is associated with a significantly enhanced antibody response to Hib in children aged between 18 months and 6 years.31
Overview of HIV Infection
Published in Mark J. Rosen, James M. Beck, Human Immunodeficiency Virus and the Lung, 1998
Simberkoff MS, Sadr WE, Schiffman G, Rahal JJ. Streptococcus pneumoniae infections and bacteremia in patients with acquired immune deficiency syndrome with report of pneumococcal vaccine failure. Am Rev Respir Dis 1984; 130:1174-1176.
Influenza vaccine failure: failure to protect or failure to understand?
Published in Expert Review of Vaccines, 2018
While imperfect, influenza vaccines are a critical part of the influenza-prevention armamentarium. Unfortunately, physicians, nurses, pharmacists, the media, and others commonly use the term ‘vaccine failure’ without understanding the circumstances under which a vaccine did or did not fail in what it is expected to do. This can lead to false claims of ‘vaccine failure,’ increased mistrust in influenza vaccines, and a bias against receiving vaccine. Influenza vaccine can only provide maximum protection to the extent that the circulating and vaccine strains closely match; the vaccine is stored, handled, and administered properly and within a time frame that results in protective levels of immunity and is administered to an immunocompetent host in which genetic restriction does not prevent development of protective immune responses. In addition, development and use of a proper framework and nosology for describing and identifying vaccine failure can assist in efforts to study and identify actual mechanisms of documented vaccine failure that may be amenable to improvement.
Novel developments of hepatitis B: treatment goals, agents and monitoring tools
Published in Expert Review of Clinical Pharmacology, 2019
Lung-Yi Mak, Wai-Kay Seto, James Fung, Man-Fung Yuen
The widespread use of the 3-dose HBV vaccine has dramatically reduced the prevalence of chronic HBV in children under age of 5. The prevalence of CHB in this age group dropped from 4.7% in the pre-vaccination era to 1.3% in 2015 [4]. The persistence of infection despite vaccination is mainly due to two reasons: incomplete vaccine coverage in many countries and vaccine failure in highly viremic mothers. In 2015, it is estimated that only 39% of the babies born worldwide received birth dose vaccine funded by Global Alliance for Vaccines and Immunization (GAVI), as many births in GAVI-supported countries occur outside hospitals [1,4]. Failure of vaccine protection can also occur, mostly in babies of highly viremic mothers who are usually HBeAg-positive with serum HBV DNA more than 6 log10 copies per milliliter [11]. These mothers should receive tenofovir disoproxil fumarate (TDF) during the latter stage of pregnancy until post-partum, which can reduce the risk of perinatal transmission, in conjunction with vaccination and passive immunization [12]. Not only would new-born HBV immunization lead to reduced incidence of newly acquired CHB, but also a reduction in the incidence of HCC [13,14]. With these undoubted benefits of HBV vaccine in newborns and infants, the World Health Organization (WHO) sets a target in achieving 90% of birth dose coverage globally by the year 2030. Other measures to reduce new HBV infection include vaccination of high-risk adults such as health-care providers and those with history of injected drug use [15]. Recently, a recombinant adjuvanted HBV vaccine (HBsAg-1018) was approved by the U.S. Food and Drug Administration with a unanimous vote in November 2017 for use in adults to prevent CHB infection, with no black box or safety concerns nor any cardiac issues [16]. This vaccine is administered for 2 doses (4 weeks apart) instead of 3 doses (over 6 months) as in Engerix-B® and Recombivax®, without compromising the immunogenicity despite a more convenient dosing schedule [17]. With the implementation of these strategies and enhanced uptake of vaccination, the World Health Assembly approved a global strategy to reduce new infections by 90% by the year 2030.
Application of hepatitis B immunoglobulin in prevention of mother-to-child transmission of chronic hepatitis B in HBsAg- and HBeAg-positive mother
Published in Journal of Obstetrics and Gynaecology, 2022
Hong Wang, Jia Wei Fang, Zhao Wen Gu, Dong Jie Song, Yuan Chen, Guang Di Chen, Baihui Zhao, Ce Sun, Yue Ma, Ke Xin Wang, Jia Qi Shen, Xiao Fu Yang, Qiong Luo
Currently, the ‘0-1-6’ immunoprophylaxis programme has been widely adopted in China as mentioned before and the blocking rate of MTCT has increased significantly, but there still remain a few cases confronted with vaccine failures as presented in this study. Potential factors incurring vaccine failure may include immune tolerance, viral mutations, low interleukin-2 (IL-2) activity, immunodeficiency, and dosage of HBVac and HBIG (Weissman et al. 1988; Preboth 2000; Fan et al. 2016). High-load DNA during pregnancy has always been a highlighting risk factor for MTCT of HBV (Xu et al. 2002; Jin et al. 2014). In this prospective study, five infants in the 200 IU injection group got immunisation failures, of which four pregnant women had high-load DNA before labour. The two immunisation failure babies in the 100 IU injection group were both born to pregnant women with high-load DNA before labour, implying high DNA load a risk factor which led to vaccine failure, but no significant difference was found in terms of the efficacy on blocking MTCT of HBV between the 100 IU and 200 IU injection groups plus HBVac for HBsAg- and HBeAg-positive pregnant women regardless of DNA load before labour. The 200 IU group didn’t show a better seroprotection rate than the 100 IU group (100 IU vs. 200 IU: 97.01% vs. 93.55%, p = .427) at high DNA load, which means that 100 IU HBIG may be able to exert sufficient immune blocking effect. Binary Logistic regression analysis showed that the OR value of DNA load was 0.11 (p = .043) after independent variable selection, which indicated that higher-dosage HBIG is not necessary for higher-viral-load pregnant women, but high-load DNA is still a risk factor for both 100 IU and 200 IU group. Thus, antiviral therapy during pregnancy is recommended to cut down MTCT rate of HBV. The previous work has indicated that usage of oral antiviral drugs, like telbivudine, in the second and third trimester can temporarily reduce the maternal HBV viral load, thereby safely and effectively reducing the risk of MTCT (Preboth 2000; Wiseman et al. 2009). Pregnant women receiving anti-viral prophylaxis during the third trimester can prevent additional chronic infections in newborns compared with those without antiviral treatment (Fan et al. 2016), and the WHO-recommended tenofovir-containing regimens are also highly effective against HBV infection. But due to the small sample sizes, the lack of formal prevention of neonates, and the occurrence of mother-to-child transmission after antiviral treatment in previous studies, the results of the study are still lacking in rigour and universality, so we still cannot formulate a perfect indication aimed for the application of antiviral drugs for pregnant women in China. In addition, studies indicated that 100 IU or 200 IU HBIG can be applied not only to neonates but also during pregnancy to reduce replication of HBV and viral load in maternal blood (Yi et al. 2016), but the effect of antenatal HBIG administration to pregnant women on newborn outcomes is still controversial (Shi et al. 2010; Eke et al. 2017).