Broad-spectrum pan-genus and pan-family virus vaccines.

Although the development and clinical application of SARS-CoV-2 vaccines during the COVID-19 pandemic demonstrated unprecedented vaccine success in a short time frame, it also revealed a limitation of current vaccines in their inability to provide broad-spectrum or universal protection against emerging variants. Broad-spectrum vaccines, therefore, remain a dream and challenge for vaccinology. This review will focus on current and future efforts in developing universal vaccines targeting different viruses at the genus and/or family levels, with a special focus on henipaviruses, influenza viruses, and coronaviruses. It is evident that strategies for developing broad-spectrum vaccines will be virus-genus or family specific, and it is almost impossible to adopt a universal approach for different viruses. On the other hand, efforts in developing broad-spectrum neutralizing monoclonal antibodies have been more successful and it is worth considering broad-spectrum antibody-mediated immunization, or "universal antibody vaccine," as an alternative approach for early intervention for future disease X outbreaks.

TOPLUM BAĞIŞIKLIĞI VE HALKA BAĞIŞIKLAMA

Bağışıklama hizmetleri, insanların hastalıklardan korunmasında ve ölümlerin önüne geçmede son derece önemli halk sağlığı müdahalelerinden biridir. Günümüzde 20'den fazla hastalığa karşı aşı geliştirilmiş olmakla birlikte pek çok kişinin aşılara erişimi yetersizdir. Bununla birlikte sadece bazı kişilerin değil, toplumun tamamının aşılanması tercih edilmektedir. Bu kapsamda toplum bağışıklığından bahsedilmektedir. Toplum bağışıklığı, aşı veya hastalığı geçirme sonucu o hastalığa karşı bağışıklık kazananlar sayesinde diğer kişiler için hastalık bulaşmasına neden olacak karşılaşma riskini azaltır. Bu sayede salgınların önlenmesi ve olası bir salgında da morbidite ve mortalitenin sınırlanması sağlanır. Toplum bağışıklığından bahsedebilmek için her hastalık için değişen değerlerde, toplumun belli bir oranda bağışık olması gerekmektedir. Bu;bazen ekonomik, lojistik vb. etkenler sebebiyle mümkün olamadığında halka bağışıklama (ring vaccination) gibi başka bağışıklama stratejilerinin düşünülmesi söz konusu olabilmektedir. Halka bağışıklığı, enfekte vaka etrafındaki bir "halka" içindeki herkesin aşılanması ile vaka etrafında bir bağışıklık tamponu oluşturmayı amaçlamaktadır. Toplum bağışıklığını tamamlayıcı olarak kullanılabileceği gibi yetersiz kaynak olan toplumlarda toplum bağışıklığı sağlanamıyorsa ve sporadik olarak görülen hastalıklarda tek bağışıklama stratejisi olarak da tercih edilebilmektedir. Bu yaklaşım, COVID-19 salgınında belli durumlarda da uygulanabilirliği açısından değerlendirme aşamasındadır.Alternate : Immunization services are one of the most important public health interventions to protect people from diseases and prevent deaths. Although vaccines have been developed against more than 20 diseases today, many people have insufficient access to vaccines. However, it is preferable to vaccinate not only some people but also the entire society. In this context, herd immunity is mentioned. Herd immunity reduces the risk of encounters that will cause disease transmission to other people, thanks to those who have become immune to that disease as a result of vaccination or exposure to the disease. In this way, it is ensured that epidemics are prevented and morbidity and mortality are limited in a possible epidemic. In order to talk about herd immunity, society should be immune to a certain extent, with varying values for each disease. This;is sometimes economic, logistics etc. when this is not possible due to various factors, other immunization strategies such as ring vaccination may be considered. Ring vaccination aims to create an immune buffer around the case by vaccinating everyone in a "ring" around the infected case. It can be used as a complement to herd immunity or be preferred as the only immunization strategy in societies with insufficient resources if herd immunity cannot be provided and in sporadic diseases. This approach is under evaluation in terms of its applicability in certain situations in the COVID-19 outbreak.

SARS-CoV-2 in Africa.

The earliest cases of COVID-19 disease in Africa were, in most cases, the result of imports from abroad. The Democratic republic of the Congo (DRC) identified the first case at the beginning of 2020. Two days after his return from France, the first patient was tested positively in the capital, Kinshasa. The travel restrictions and status of the state of emergency were announced on 24 March 2020. A lockdown followed. In June of the same year, 11 provinces were already affected by COVID-19 disease. The negative socio-economic impact has occurred and is similar to that in any other country. The DRC does not differ from other African countries or on the issue of infectious diseases such as HIV, malaria, cholera, measles or Ebola virus disease. Recurring Ebola epidemics are addressed by vaccination with Ervebo vaccine. Unlike Ebola, part of the population does not believe in the existence of SARS-CoV-2 and does not respect basic anti-epidemic measures. Medical capacities were very limited at the beginning of the SARS-CoV-2 epidemic, both in terms of diagnosis and testing and availability of treatment (60 ventilators to 83 million inhabitants). The situation is complicated as a result of 20 years continuing wars. Another African country, Guinea, is currently facing not only COVID-19, but also the zoonotic disease of Lassa fever, which has been detected in several patients. Copyright © 2021, Medakta s.r.o.. All rights reserved.

Considerations on the clinical development of COVID-19 vaccine from trial design perspectives.

COVID-19 has become a global pandemic, and an effective vaccine is needed. During the outbreak, the urgency for developing candidate vaccines has brought distinct challenges to clinical development. An efficacy trial, which measures whether the vaccine reduces the incidence of disease, is ordinarily required to fully evaluate vaccine efficacy. However, emergency use may be possible if promising immunogenicity results are observed. A ring vaccination trial, which recruits subjects connected to a known case either socially or geographically, is a solution to evaluate vaccine efficacy and control the spread of the disease simultaneously although its conduct is challenging. Nevertheless, when COVID-19 becomes a recurrent epidemic, an 'individual-level' efficacy trial is preferred. Innovative statistical designs, including seamless design, platform trial, master protocol design, are helpful to accelerate clinical development. A seamless Phase I/II design has been applied in multiple COVID-19 vaccine studies to date. However, Phase II/III design should be done very carefully. The control of type I error, maintaining trial blinding and statistical methods leading to unbiased estimates should be pre-specified in the clinical protocol. A Data Safety Monitoring Board is especially important, given the need to assure an adequate level of safety when society want a safe and effective vaccine.