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Taming the Enemy
Published in Norman Begg, 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
Published in Patricia G. Melloy, 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.
The Viruses
Published in Julius P. Kreier, Infection, Resistance, and Immunity, 2022
The attenuated Sabin vaccine and the inactivated Salk vaccine contain the capsid proteins of the three major serotypes of poliovirus. Immunity is conferred by the induction of virus-neutralizing antibodies to the capsid proteins. These neutralizing antibodies prevent infection of neurons. Compared to inactivated vaccines, attenuated live vaccines require smaller initial quantities of virus, and viral replication is required for induction of immunity. They must therefore be handled carefully during distribution and use to prevent inactivation and ensure infectivity. The major advantage of the inactivated vaccine, despite the need for larger initial amounts of virus, is that inactivation eliminates the possibility of reversion to the wild type virus.
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.
Approaches in broadening the neutralizing antibody response of the influenza vaccine
Published in Expert Review of Vaccines, 2021
Ruiqi Zhang, Ivan Fan-Ngai Hung
The virus used to produce the inactivated vaccine are cultured in chicken embryonated eggs or cell lines [26,27]. Then, the virus is inactivated with formaldehyde or β-propiolactone [25]. The current inactivated influenza vaccines include quadrivalent and trivalent influenza vaccines. The quadrivalent vaccine consists of H1N1, H3N2, and two influenza B virus strains (Victoria-like strain and Yamagata-like strain), while H1N1, H3N2 and one influenza B virus for trivalent vaccines [27]. Normally, the inactivated vaccine has high safety and can be administrated to persons more than 6 months and older including pregnant women [28]. The human influenza virus needs to be passed on eggs several times to adapt to chicken embryos and achieve a high yield [29–31]. However, the adaptation to chicken embryonated eggs could introduce some mutations which will alter the antigenicity of viral proteins to influenza virus, resulting in the low effectiveness of vaccine [29]. The inactivated vaccine may contain antigen from eggs and cell lines due to the method of production, and then trigger related allergies.
Risk of herpes zoster with IL-17 inhibitor therapy for psoriasis and other inflammatory conditions
Published in Journal of Dermatological Treatment, 2020
Kevin K. Wu, Michael P. Lee, Erica B. Lee, Jashin J. Wu
Vaccination reduces the incidence of HZ and the duration and severity of postherpetic neuralgia caused by HZ (51). Current population-based guidelines established by the Center for Disease Control recommend HZ vaccination for adults over the age of 60 regardless of a prior history of HZ (52). Two HZ vaccines are currently available: inactivated zoster vaccine recombinant, adjuvanted (Shinrix®) and live zoster vaccine (Zostavax®) (53,54). The inactivated vaccine is newer and significantly more expensive. However, because it is an inactivated vaccine, it may be used in those with a compromised immune system, including those on biologic medications. In contrast, the live vaccine is contraindicated in patients treated with ≥20 mg of prednisone or any biologic (52,54). In addition, the new inactivated vaccine is substantially more effective; the inactivated vaccine had an efficacy rate of 97.2% (95% CI, 93.7–99.0), while the live vaccine had an efficacy rate of 50–64% (55). Common side-effects of the live vaccine include injection site reactions, headache, diarrhea, joint/muscle pain, or skin rash. Common side-effects of the inactivated vaccine include injection site reaction, myalgia, fatigue, headache, fever, and gastrointestinal symptoms. There are currently no clinical guidelines regarding HZ vaccination prior to starting an IL-17 inhibitor. However, if vaccination is planned prior to beginning therapy, it should be completed at least 14 days prior to the initiation of therapy to allow sufficient time for the immune system time to respond to the vaccine (52).