key: cord-0952811-60uuhhvs authors: Charla, Yashika; Kalra, Manas; Chopra, Neha; Choudhury, Sangeeta title: COVID‐19 vaccination in pediatric cancer patients: A high priority date: 2021-10-11 journal: Pediatr Blood Cancer DOI: 10.1002/pbc.29397 sha: 23ce00dacf88d4d4823e6c43c65b237c0d4c1658 doc_id: 952811 cord_uid: 60uuhhvs nan Global COVID-19 burden continues to be on rise, affecting every facet of the health care system. The adult population has been severely affected during both waves of the pandemic including cancer patients and immunocompromised hosts who have shown higher susceptibility, morbidity, and mortality. [1] [2] [3] The rate of SARS-CoV-2 infectivity in children has been low but there has been speculation that children will be more affected in future waves. 4 The second wave has done far more damage in countries like India with the severity of viral infection being much greater and the virus affecting more of the younger population. This trend has been observed across many countries. 5, 6 A study reported a median of two COVID-19 pediatric cancer cases per institution from a total of 213 institutions across 79 countries, of which 24% of the institutions reported no cases in children. 7 The majority of the children presented with asymptomatic or mild form of infection, 8 but can be COVID-19 positive and can develop Kawasaki-like disease or multisystem inflammatory syndrome in children (MIS-C). Hospital stays and reported deaths are much less than in adults, who often suffer from lower respiratory infection. 6, 9, 10 Why are children less affected by SARS-CoV-2? "Trained innate immunity" due to continuous exposure with infectious diseases in early childhood may be one of the reasons 11 apart from the age-related differences in immune response to virus, especially at the nasal mucosal site. Heightened innate immune responses due to frequent respiratory infections and recent immunization to other common infections like influenza, tuberculosis, and so forth are also unique to pediatric group. 12 It is known that S-protein of SARS-CoV-2 binds to host cell ACE2 surface receptor. As children express low levels of ACE2 receptors, they are less prone to infection. 13 Another reason could be increased number of lymphocytes especially NK cells providing immu-nity against virus. 14 Cumulative innate immunity factors contribute to the differential severity of the disease in children. 15 Yet, SARS-COV-2 infections in children with cancer show higher mortality and more complications. In one study, 17% of children with cancer were positive for SARS-CoV-2 and 25.5% among these were asymptomatic while 7.14% required mechanical ventilation and 25.5% were under oxygen supplementation with mortality 4%. 16 A systematic review showed that almost 10% of children with an underlying diagnosis of cancer developed severe disease and 32% needed oxygen support with a mortality rate of 5%. This indicates that children with cancer are vulnerable to serious effects of this virus. 17 A study conducted in our hospital's pediatric oncology unit revealed that 13.8% children needed oxygen therapy and an equal number needed admission to the intensive care unit. 18 One of the major complications that children develop after COVID-19 infection is MIS-C. It often develops 1-6 weeks postinfection and can presentat like Kawasaki disease. 19, 20 It is known that the immune status of children with malignancies is altered. Further, treatment with anticancer drugs weakens the immune system more. In fact, with the spread of SARS-CoV-2, cancer care in children has suffered collateral consequences in terms of decreased access to diagnosis and challenges in undertaking effective therapy. surgical rates, 60% blood shortages, 57% chemotherapy modifications, and 28% interruption in radiotherapy services. 7 Not only low-and middle-income countries, but also the most advanced pediatric oncology centers in the world reported deaths, high incidence of oxygen therapy, delays in chemotherapy (54%), and postponements in surgery (46%) and stem cell transplant (30%). 16, 21 The coming months to years may see an increase in relapse of childhood cancers secondary to interruptions in timely therapy. inappropriate. This is because of the differences in biology and types of cancers, with hematological malignancies being more common in children. The immune response generated in these patients is very different from those with solid tumors. 24 Recently, similar efforts of conducting COVID-19 vaccination clinical trials in children have been initiated although in smaller proportion than adults. The primary outcomes are safety, efficacy, immunogenicity, and reactogenicity among healthy children across the globe, detailed in Table 1 The authors declare that there is no conflict of interest. The manuscript was written through contribution of all authors. All authors have given approval to the final version of the manuscript. Yashika Charla and Manas Kalra equally contributed toward drafting the manuscript. Manas Kalra also edited and proofread the manuscript. Neha Chopra contributed to advising and editing the manuscript. Sangeeta Choudhury conceptualized, guided, framed, and edited the manuscript. 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