RNA Vaccines against Infectious Diseases: Vital Progress with Room for Improvement

[Highmark]

https://www.mdpi.com/2076-393X/9/11/1211/htm

Received: 6 July 2021 / Revised: 12 August 2021 / Accepted: 13 August 2021 / Published: 20 October 2021

 

7. Challenges Faced by RNA Vaccination Technologies

7.1. Safety and Tolerability

Although the rapid pace of RNA vaccine development raised some level of hesitation against RNA vaccines, these vaccines surpass other traditional vaccines in having the potential to be much safer as they are considered noninfectious platforms that lack the viral structure, and the replicon does not produce infectious viral particles. Additionally, RNAs are also nonintegrating, and they do not integrate into the host genome and are degraded during the process of antigen expression. The main concern about safety of RNA vaccines is the possibility that these vaccines may generate strong type I interferon and proinflammatory cytokines responses that can promote the development of autoreactive B cells and T cells, posing an even greater threat which could lead to inflammation and autoimmune conditions [88,89]. One study reported the safety of mRNA vaccines among pregnant women who did not show obvious safety signals after receiving COVID-19 mRNA vaccines and recommended more longitudinal follow-up in order to identify maternal, pregnancy and infant outcomes [90]. Moreover, several studies tackled the safety and reactogenicity of SARS-CoV-2 mRNA vaccines in organ transplant recipients since immunosuppressed patients were excluded from original vaccine trials and reported no major safety concerns. In addition, symptoms were consistent with vaccine reactogenicity demonstrated in original clinical trials in healthy adults and those with stable, chronic medical condition [91]. Although two doses of mRNA vaccines elicited considerable immune response in organ recipients considering limited protection is better than none, a study suggests that many transplant recipients may remain at risk for COVID-19 after two doses of mRNA vaccine [92]. To overcome this issue, recommendation for a booster dose of mRNA vaccine to be administered to organ transplant recipients needs to be considered for better protection of those immunocompromised patients [93,94]. Data still need to tackle other safety aspects bearing in mind vulnerable populations, including children, elderly and patients with chronic conditions such as autoimmune disorders. Furthermore, RNA vaccine compatibility with different medical drugs also needs thorough evaluation. Thus, active and sentinel surveillance became a must to meticulously monitor and assess the safety profile of the vaccines

 

7.3. Efficacy and Protection

The long-term efficacy and possible side effects of RNA vaccines are still obscure. A vaccine is considered efficient when it generates desired humoral and cellular immunity against the pathogen, besides minimizing adverse events. mRNA vaccine efficacy against COVID-19 was addressed in a study for the United States Centers for Disease Control and Prevention (CDC) that involved the two authorized mRNA vaccines for COVID-19: mRNA-1273 and BNT162b2. The study showed promising effectiveness of partial or full vaccination among hospitalized adults aged ≥65 years who are at higher risk of the disease [29]. The adjusted vaccine effectiveness (VE) was estimated to be 94% for full vaccination and 64% for partial vaccination, which corresponds with the efficacy on the same subgroup in clinical trials [29]. These findings are also consistent with the study that addressed the real-world effectiveness of SARS-CoV-2 vaccination by BNT162b2 including older adults [55]. On the other hand, variants of concern (VOCs) may reduce vaccine effectiveness, which may be evident by a high number of vaccine breakthrough cases or a very low vaccine-induced protection against severe disease. Currently, enhanced genomic surveillance in some countries has detected six variants of SARS-CoV-2 circulating; B.1.1.7 (first detected in the United Kingdom), B.1.351, the P.1 (first detected in Brazil), B.1.526 and B.1.525 (first detected in New York), B.1.427 and B.1.429 (first detected in California) and the B.1.617 variant that recently emerged in India. A study conducted by Goel et al. showed that mRNA-1273 and BNT162b2 mRNA vaccines elicit neutralizing titers against the B.1.351 South African variant that skyrocketed after the first dose in recovered subjects [96]. However, another study tested pseudovirus bearing the B.1.1.7 lineage spike protein with sera of study participants who were previously vaccinated with BNT162b2 showed a sixfold reduction of neutralization for the majority of sera yet preserved neutralizing titers against the B.1.1.7 lineage pseudovirus [97]. Despite being a highly contagious variant that is dominating nationwide, mRNA vaccines showed to offer protection and sustained effectiveness against the B.1.617.2 variant as well. A study held in Scotland showed that Pfizer-BioNTech mRNA vaccine demonstrated 79% effectiveness against COVID-19 after 14 days from receiving the second dose [98]. These results are consistent with the data published by Public Health England that reported 88% effectiveness after two doses of BNT162b2 [99]. Although mRNA vaccines are still efficient against the evolving circulating VOCs till this date, these variants still pose further concerns on whether mRNA vaccines will still be efficient in combating these rapidly mutating variants in the future or not.

[Rod]

If covid was a serious concern to me then maybe this type of medical treatment would be worth the risks 

but it’s all so dumb my best bet is to just keep ignoring all of it 

[Highmark]

33 minutes ago, ACE said:

If covid was a serious concern to me then maybe this type of medical treatment would be worth the risks 

but it’s all so dumb my best bet is to just keep ignoring all of it 

For many the benefit outweighs the risk however I agree for this pathogen and the current variants I don't feel the correct path is jabbing every single person on earth which is exactly what they are pushing even when they fully admit the long term side effects are obscure. 

Edited December 7, 2021 by Highmark

[Rod]

Just now, Highmark said:

For many the benefit outweighs the risk however I agree for this pathogen I don't feel the correct path is jabbing every single person on earth which is exactly what they are pushing even when they fully admit the long term side effects are obscure. 

It’s just for profit. Covid has become a multi billion dollar industry 

there is zero sound or logical reason to jab every living soul for covid. The only real reason is corporate profits. 
 

there’s people that can benefit from these medical treatments but it takes an incredibly weak mind to think that everyone needs it 

[Highmark]

1 minute ago, ACE said:

It’s just for profit. Covid has become a multi billion dollar industry 

there is zero sound or logical reason to jab every living soul for covid. The only real reason is corporate profits. 
 

there’s people that can benefit from these medical treatments but it takes an incredibly weak mind to think that everyone needs it 

Don't kid yourself its also about govt control.

[Rod]

1 minute ago, Highmark said:

Don't kid yourself its also about govt control.

Everyone is trying to capitalize on it anyway that they can