New Trends in Antiviral Therapy of CNS Infections
Sunit K. Singh, Daniel Růžek in Neuroviral Infections, 2013
Currently, there are a number of ongoing clinical trials for WNV vaccines. There is an inactivated virus vaccine (Samina et al. 2005), a formalin-inactivated whole virus vaccine (Arroyo et al. 2004), a vaccine that involves the production of antigens from a heterologous virus backbone, a DNA vaccine with structural antigens being expressed from DNA plasmids (Monath et al. 2006), a DNA recombinant vaccine (Davis et al. 2001), and purified protein viral proteins (Lieberman et al. 2007). It is expected that the use of these vaccines may, in the near future, efficiently prevent this infection. Similar to WNV, an effective vaccine to prevent dengue fever has been sought. Many approaches to developing candidate vaccines have been employed. The candidates include live attenuated tetravalent vaccines, chimeric tetravalent vaccines based on attenuated dengue virus or Yellow Fever 17D, and recombinant DNA vaccines based on flavivirus and nonflavivirus vectors (Murrell et al. 2011).
Taming the Enemy
Norman Begg in The Remarkable Story of Vaccines, 2023
An inactivated vaccine is made by killing the virus or bacterium, either chemically or with heat. The virus or bacterium in an inactivated vaccine is dead, incapable of multiplying, also known as non-replicating. Many of the early vaccines of the nineteenth century such as rabies, typhoid and cholera were made by inactivation, and a few modern vaccines such as polio and hepatitis A still use this method. Their inability to multiply makes them very safe; however, they tend to provide protection which doesn’t last for long, so booster injections have to be given. Inactivated polio vaccines need three initial doses, followed by two boosters, to provide full protection. This protection lasts for ten years, so if you travel somewhere that there is still polio and it is more than ten years since your last vaccination, you will need a further booster.
An Introduction to the Immune System and Vaccines
Patricia G. Melloy in Viruses and Society, 2023
There are many kinds of vaccines, including those made from live, attenuated (disabled) pathogens, those made from dead pathogens, and those made from parts of the pathogen itself, which can be made in a cellular system using recombinant DNA technology (Coico and Sunshine 2015). Typically, the vaccines made from part of a pathogen, such as a virus, are nucleic acid–based (Ahmed, Ellis, and Rappuoli 2017). Louis Pasteur initially developed the attenuation technique using a chemical process to weaken rabies virus as well as the bacterial pathogen anthrax. Others subsequently used a technique called “passaging,” in which the virus is grown in cell culture for a period, selecting for weaker strains of the virus (Plotkin 2005). Other methods used in live vaccines include taking a related virus from another species and using it, such as the case with the smallpox vaccine using cowpox. Temperature-sensitive viral variants are also available in some cases. These are viruses that behave normally at one temperature, but then can be disabled at another temperature, usually a higher temperature. For an inactivated vaccine, scientists have created a variety of approaches, including using whole inactivated virus or just parts of it such as a viral protein, part of a viral protein, or a viral carbohydrate (Ahmed, Ellis, and Rappuoli 2017). Some of the latest vaccines, including vaccines used against SARS-CoV-2, are based on mRNA technology (Pardi et al. 2018). We will discuss the details of these vaccines in Chapter 6.
Tofacitinib for the treatment of psoriasis and psoriatic arthritis
Published in Expert Review of Clinical Immunology, 2018
Anna Berekmeri, Farrouq Mahmood, Miriam Wittmann, Philip Helliwell
The high incidence of HZ infection in both PsA and psoriasis patients treated with tofacitinib, especially in Japanese population, is also of some concern. The identified risk factors for HZ in tofacitinib treated patients include: Asian race, increased age, higher dose and prior biologic exposure [32]. Vaccination against HZ prior to starting the drug may be considered. Patients should at least be counselled about the risk of HZ when being initiated on treatment. The current vaccine available is a live vaccine, although an inactivated vaccine has recently been developed and approved for use by the CDC. According to the summary product characteristics for tofacitinib it is not recommended that live vaccines be given concurrently with the drug, but should be administered preferably at 4 weeks prior to drug initiation or in accordance with vaccination guidelines in reference to immunosuppressive medications [33]. Downregulated molecules are believed to have an impact on persistent viral infection control (i.e. IL-21) raising slight concerns regarding the risk of slow viral diseases of the central nervous system––although there is no current data supporting this concern.
Current status of COVID-19 vaccination: safety and liability concern for children, pregnant and lactating women
Published in Expert Review of Vaccines, 2022
Swagat Kumar Das, Manish Paul, Bikash Chandra Behera, Hrudayanath Thatoi
Nonetheless, the downside of this sort of vaccine is that the vaccine’s effectiveness is negatively affected by the vector immunity and the type of vector chosen. The advantage of vaccine candidates developed using replicating viral vectors is that the immune system is stimulated similar to natural infection. However, the disadvantage is the low vaccine production as only one or fewer copies of provirus are expressed per cell. The expression of proviruses is sensitive to chromosomal position effects as well as DNA repeats and introns. In the development of live attenuated vaccines, a simple technique is employed in conjunction with existing infrastructure. The downside of generating this form of vaccination is that it takes time to create the infectious clones for attenuated coronavirus because of its large genome size. Aside from that, considerable safety testing is required during the vaccine’s development. Like a live attenuated vaccine, inactivated vaccine development also follows a straightforward method utilizing existing infrastructure. This vaccine has been tested in humans to treat SARS-CoV-1 infection. In this vaccine development, adjuvants can be used for increasing immunogenicity. Handling huge volumes of infectious viruses and ensuring the integrity of antigen or epitope are key difficulties during vaccine production.
Enhanced stability of foot-and-mouth disease vaccine antigens with a novel formulation
Published in Pharmaceutical Development and Technology, 2022
Jing Li, Rong Zhang, Huiqing Yang, Yanming Wei
Adjuvant, a key component, has an important effect on protein stability (Harmsen et al. 2015). This study showed the stability of vaccine prepared with ISA206, while the situation about other adjuvants, such as ISA201, was not clear. Thus, future investigation should be required to assess vaccine stability prepared with ISA201. In addition, antibody titer is an important parameter to evaluate vaccine quality. The problems of whether the formulation could influence the immunogenicity and whether stabilized vaccine contributes to antibody titer are the two considerable aspects to be fully considered. Therefore, further study should also take immune response in animals into account. Overall, these studies could provide a new insight into the improvement of the stability of inactivated vaccine.
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