Adverse Reactions to Vaccination: From Anaphylaxis to Autoimmunity

Pharmacovigilance in Vaccines: Importance, Main Aspects, Perspectives, and Challenges-A Narrative Review

Pharmacovigilance plays a central role in safeguarding public health by continuously monitoring the safety of vaccines, being critical in a climate of vaccine hesitancy, where public trust is paramount. Pharmacovigilance strategies employed to gather information on adverse events following immunization (AEFIs) include pre-registration data, media reports, clinical trials, and societal reporting. Early detection of AEFIs during clinical trials is crucial for thorough safety analysis and preventing serious reactions once vaccines are deployed. This review highlights the importance of societal reporting, encompassing contributions from community members, healthcare workers, and pharmaceutical companies. Technological advancements such as quick response (QR) codes can facilitate prompt AEFI reporting. While vaccines are demonstrably safe, the possibility of adverse events necessitates continuous post-marketing surveillance. However, underreporting remains a challenge, underscoring the critical role of public engagement in pharmacovigilance. This narrative review comprehensively examines and synthesizes key aspects of virus vaccine pharmacovigilance, with special considerations for specific population groups. We explore applicable legislation, the spectrum of AEFIs associated with major vaccines, and the unique challenges and perspectives surrounding pharmacovigilance in this domain.

GnRH Vaccine Could Suppress Serum Testosterone in Stallion Mules

Stallion mules have been used as working equids in several countries. Aggressiveness under the influence of testosterone results in the necessity for surgical castration before work training. The gonadotropin-releasing hormone (GnRH) vaccine may be an alternative method for immunocastration in mules. The objective of this study was to evaluate the effect of the GnRH vaccine on anti-GnRH antibody concentration, serum testosterone concentration, clinical adverse effects, and behavioral changes in response to receiving selected physical manipulations from humans. Twenty-five mules were separated into three groups: Control-intact, Control-castrated, and Treatment. The Treatment group was further divided according to condition (intact or unilateral cryptorchid) and age. The Treatment group received 195 µg of the GnRH vaccine intramuscularly at weeks 0, 4, and 8. The anti-GnRH antibody concentrations increased at weeks 6 and 10, and then they gradually decreased to baseline at week 24. The Treatment-intact-young group had the highest concentration of anti-GnRH antibody. The serum testosterone concentrations in the Treatment group were lower than before vaccination from weeks 6 to 14. Subcutaneous edema adjacent to the injection site was detected in the Treatment-intact group after booster vaccination. In conclusion, the mules responded to the GnRH vaccine, which could temporarily suppress testosterone for up to 14 weeks.

Feline Injection-Site Sarcoma and Other Adverse Reactions to Vaccination in Cats

Vaccine-associated adverse events (VAAEs), including feline injection-site sarcomas (FISSs), occur only rarely but can be severe. Understanding potential VAAEs is an important part of informed owner consent for vaccination. In this review, the European Advisory Board on Cat Diseases (ABCD), a scientifically independent board of feline medicine experts, presents the current knowledge on VAAEs in cats, summarizing the literature and filling the gaps where scientific studies are missing with expert opinion to assist veterinarians in adopting the best vaccination practice. VAAEs are caused by an aberrant innate or adaptive immune reaction, excessive local reactions at the inoculation site, an error in administration, or failure in the manufacturing process. FISS, the most severe VAAE, can develop after vaccinations or injection of other substances. Although the most widely accepted hypothesis is that chronic inflammation triggers malignant transformation, the pathogenesis of FISS is not yet fully understood. No injectable vaccine is risk-free, and therefore, vaccination should be performed as often as necessary, but as infrequently as possible. Vaccines should be brought to room temperature prior to administration and injected at sites in which FISS surgery would likely be curative; the interscapular region should be avoided. Post-vaccinal monitoring is essential.

Clinical assessment of a point-of-care assay to determine protective vaccinal antibody titers to canine viral diseases

Guidelines recommend that dogs are vaccinated for canine distemper virus (CDV), canine parvovirus (CPV), and canine adenovirus (CAV) every 3 years. Alternatively, their antibody titers are measured and vaccines given when titers fall below a protective threshold. In this study, a point-of-care (POC) assay was compared to hemagglutination inhibition (for CPV) and virus neutralization (for CAV and CDV) assays to predict the need for revaccination Ninety-two dogs presented for vaccination were enrolled. The POC assay indicated protective titers against CDV in 79/80, CPV in 89/90, and CAV in 91/91 dogs with reference standard antibody measurements that were over a protective threshold. The sensitivity of the POC assay for to detect protective concentrations of CDV antibodies was 99% (95% confidence interval [CI 95%], 93.3-99.9%). Ten dogs were falsely considered protected against CDV by the POC assay with a specificity of 17% (CI 95%, 3.0-44.8%). The sensitivity of the POC assay for protective concentrations of CPV titers was 99% (CI 95%, 93.9-99.9%). The sensitivity of the POC assay to detect protective concentrations of CAV antibodies was 100% (CI 95%, 95.9-100%). Only classifying high-positive CDV and CPV titers on the POC assay as protective improved assay specificity to 100%, but sensitivity decreased to 51% and 76% respectively. This POC assay had a high sensitivity for the detection of protective antibody titers; however, some dogs were falsely categorized as protected, especially for CDV.

SARS-CoV-2 vaccine-triggered autoimmunity: Molecular mimicry and/or bystander activation of the immune system

Induced autoimmunity or autoinflammatory-like conditions as a rare vaccine-related adverse event have been reported following COVID-19 vaccination. Such inadvertent adverse reactions have raised somewhat concerns about the long-term safety of the developed vaccines. Such multifactorial phenomena may be related to the cross-reactivity between the viral-specific antigens with the host self-proteins through molecular mimicry mechanism and/or nonspecific bystander activation of the non-target antigen-independent immunity by the entities of the vaccine products. However, due to the low incidence of the reported/identified individuals and insufficient evidence, autoimmunity following the COVID-19 vaccination has not been approved. Thereby, it seems that further designated studies might warrant post-monitoring of the inevitable adverse immunologic reactions in the vaccinated individuals, especially among hypersensitive cases, to address possible immunological mechanisms induced by the viral vaccines, incorporated adjuvants, and even vaccine delivery systems.

Neuroprotective Potentials of Flavonoids: Experimental Studies and Mechanisms of Action

Neurological and neurodegenerative diseases, particularly those related to aging, are on the rise, but drug therapies are rarely curative. Functional disorders and the organic degeneration of nervous tissue often have complex causes, in which phenomena of oxidative stress, inflammation and cytotoxicity are intertwined. For these reasons, the search for natural substances that can slow down or counteract these pathologies has increased rapidly over the last two decades. In this paper, studies on the neuroprotective effects of flavonoids (especially the two most widely used, hesperidin and quercetin) on animal models of depression, neurotoxicity, Alzheimer's disease (AD) and Parkinson's disease are reviewed. The literature on these topics amounts to a few hundred publications on in vitro and in vivo models (notably in rodents) and provides us with a very detailed picture of the action mechanisms and targets of these substances. These include the decrease in enzymes that produce reactive oxygen and ferroptosis, the inhibition of mono-amine oxidases, the stimulation of the Nrf2/ARE system, the induction of brain-derived neurotrophic factor production and, in the case of AD, the prevention of amyloid-beta aggregation. The inhibition of neuroinflammatory processes has been documented as a decrease in cytokine formation (mainly TNF-alpha and IL-1beta) by microglia and astrocytes, by modulating a number of regulatory proteins such as Nf-kB and NLRP3/inflammasome. Although clinical trials on humans are still scarce, preclinical studies allow us to consider hesperidin, quercetin, and other flavonoids as very interesting and safe dietary molecules to be further investigated as complementary treatments in order to prevent neurodegenerative diseases or to moderate their deleterious effects.

COVID-19 Vaccines for Adults and Children with Autoimmune Gut or Liver Disease

The SARS-CoV-2 pandemic raised many challenges for all patients with chronic conditions and those with autoimmune diseases, both adults and children. Special attention is paid to their immunological status, concomitant diseases, and the need for immunosuppressive therapy. All of these factors may impact their COVID-19 course and outcome. COVID-19 vaccination is accepted as one of the most successful strategies for pandemic control. However, individuals with immune-mediated chronic diseases, including autoimmune liver and gut diseases, have been excluded from the vaccine clinical trials. Therefore, we rely on real-world data from vaccination after vaccine approval for these patients to fill the evidence gap for the long-term safety and efficacy of COVID-19 vaccines in patients with autoimmune gut and liver diseases. Current recommendations from inflammatory bowel disease (IBD) societies suggest COVID-19 vaccination in children older than 5 years old, adults and even pregnant females with IBD. The same recommendations are applied to patients with autoimmune liver diseases. Nevertheless, autoimmune disease patients still experience high levels of COVID-19 vaccine hesitancy, and more studies have to be conducted to clarify this issue.

Autoimmune inflammatory rheumatic diseases post-COVID-19 vaccination

Vaccination against COVID-19 is one of the critical tools to provide herd immunity, reduce mortality, and control the pandemic worldwide. Despite the safety of vaccination against SARS-CoV-2 in the healthy population, a minority of people may develop rare post-vaccine adverse reactions such as autoimmune syndromes. The current study aimed to identify and present a series of patients with de-novo autoimmune rheumatic diseases (ARDs) associated with COVID-19 vaccines. Inclusion criteria were the onset of ARDs symptoms at ∼3-4 weeks post-vaccination, age ≥ 16, no previous history of ARDs, meeting the classification criteria for one of the ARDs, and staying in the follow-up. The most commonly used vaccines in patients were Sinopharm [7 cases (50%)] and AstraZeneca [6 cases (42.9%)]. ARDs were significantly more common in subjects who received the AstraZeneca vaccine than in those who received other vaccines. Based on the results, patients were diagnosed with rheumatoid arthritis or one of its subtypes (5 cases), vasculitis (4 cases), systemic lupus erythematosus (3 cases), and peripheral seronegative spondyloarthritis (2 cases). Except for one patient with self-limitation of ARD, others were treated with disease-modifying antirheumatic drugs, and one case developed irreversible neurological complications. Indeed, our data can warn physicians about the possibility of ARDs post-vaccination, lead to faster diagnosis, prevent loss of window of opportunity for treatment, and prevent irreversible organ damage. Based on the published literature, autoimmune phenomena post-COVID-19 vaccination may be related to the overstimulation of mediators and cytokines due to complicated antigen-specific/non-specific immunological responses and mechanisms.

2022 AAHA Canine Vaccination Guidelines

These guidelines are an update and extension of previous AAHA peer-reviewed canine vaccination guidelines published in 2017. Vaccination is a cornerstone of canine preventive healthcare and one of the most cost-effective ways of maintaining a dog's health, longevity, and quality of life. Canine vaccination also serves a public health function by forming a barrier against several zoonotic diseases affecting dogs and humans. Canine vaccines are broadly categorized as containing core and noncore immunizing antigens, with administration recommendations based on assessment of individual patient risk factors. The guidelines include a comprehensive table listing canine core and noncore vaccines and a recommended vaccination and revaccination schedule for each vaccine. The guidelines explain the relevance of different vaccine formulations, including those containing modified-live virus, inactivated, and recombinant immunizing agents. Factors that potentially affect vaccine efficacy are addressed, including the patient's prevaccination immune status and vaccine duration of immunity. Because animal shelters are one of the most challenging environments for prevention and control of infectious diseases, the guidelines also provide recommendations for vaccination of dogs presented at or housed in animal shelters, including the appropriate response to an infectious disease outbreak in the shelter setting. The guidelines explain how practitioners can interpret a patient's serological status, including maternally derived antibody titers, as indicators of immune status and suitability for vaccination. Other topics covered include factors associated with postvaccination adverse events, vaccine storage and handling to preserve product efficacy, interpreting product labeling to ensure proper vaccine use, and using client education and healthcare team training to raise awareness of the importance of vaccinations.

Various painful oral adverse reactions following COVID-19 vaccination: a case series

Background

Adverse events are increasingly being reported with the growing COVID-19 vaccination rate. However, the current literature on orofacial adverse effects following COVID-19 vaccination are severely limited. With the continuation of the global vaccination campaign the incidence of oral adverse effects will inevitably increase.

Case presentation

Clinical characteristics and treatment results of nine patients who complained of pain and discomfort of the oral cavity following SARS-CoV-2 vaccination were analyzed. Swelling and pain of the posterior palatal area, pain on palatal area of the central incisor, pain on the mucosa of the lip and lower gingiva, right preauricular region and right posterior lower gingiva, the buccal mucosa, tongue, and the right lower second molar area were the reported symptoms. Ulceration and swelling of the oral mucosa were found in certain cases. The symptoms were generally mild and responded well to medication within a relatively short period of time.

Conclusion

Oral adverse reactions following COVID-19 vaccination were manageable with treatment. Clinicians should understand the true nature of orofacial adverse reactions following COVID-19 vaccines and guide patients in decision-making.

[Life-threatening acute neutrophilic vasculitis in a Shar-Pei puppy]

A 3-month old male Shar-Pei was presented for lethargy, fever and cutaneous edema. Further investigations revealed superficial pyoderma with Streptococcus canis and an acute neutrophilic vasculitis. Symptomatic and antibiotic treatment in combination with immunosuppressive treatment (initially prednisolone, later cyclosporine) treatment was performed. In the course of the disease complications such as dyspnea, anemia, skin ulceration, skin necrosis and secondary bacterial skin infection with multiresistant bacteria occurred. After intensive care treatment the dog was discharged from the hospital 38 days later. Within the following weeks the dosage of the immunosuppressants were reduced and the drugs were discontinued after 4 months.

Is Booster Dose Strategy Sufficient for Omicron Variant of SARS-CoV-2?

The Omicron variant of SARS-CoV-2 is emerging in communities where people were previously infected with SARS-CoV-2 and are now being vaccinated, or where many people have received two or three coronavirus vaccination doses. More than 130 countries around the globe have implemented booster dose programs for tackling omicron endemics. Despite early findings shows that booster doses may improve omicron protection, more research is needed to establish vaccination efficacy. This short communication tries to critically discuss the research work findings around booster dose strategy for omicron endemics.

Safety & effectiveness of COVID-19 vaccines: A narrative review

There are currently eight vaccines against SARS-CoV-2 that have received Emergency Use Authorization by the WHO that can offer some protection to the world's population during the COVID-19 pandemic. Though research is being published all over the world, public health officials, policymakers and governments are collecting evidence-based information to establish the public health policies. Unfortunately, continued international travel, violations of lockdowns and social distancing, the lack of mask use, the emergence of mutant strains of the virus and lower adherence by a sector of the global population that remains sceptical of the protection offered by vaccines, or about any risks associated with vaccines, hamper these efforts. Here we examine the literature on the efficacy, effectiveness and safety of COVID-19 vaccines, with an emphasis on select categories of individuals and against new SARS-CoV-2 strains. The literature shows that these eight vaccines are highly effective in protecting the population from severe disease and death, but there are some issues concerning safety and adverse effects. Further, booster shots and variant-specific vaccines would also be required.

Reactive arthritis after COVID-19 vaccination

The severe acute respiratory syndrome coronavirus 2-induced coronavirus disease 2019 (COVID-19) has had a global spread. Vaccines play an essential role in preventing the spread. However, almost all types of vaccines have been reported to be associated with adverse events. Reactive arthritis (ReA) after vaccination has been reported; however, ReA after COVID-19 vaccination has not been reported. We reported a 23-year-old woman who suffered from an acute ReA on her left knee joint after COVID-19 vaccination and discussed the etiology and preventive strategy. She presented with swollen, painful left knee joint for 18 d. She had been inoculated 0.5 ml CoronaVac vaccine on 0 d and the 14th day with deltoid intramuscular injection. Finally, she was diagnosed as ReA after CoronaVac vaccination and was administered a single intra-articular injection of 1 ml compound betamethasone. The swelling and pain nearly disappeared after 2 d. On 1month follow-up, her condition was normal. ReA after COVID-19 vaccination is rare. The benefits of vaccination far outweigh its potential risks and vaccination should be administered according to the current recommendations. Further attentions should be put to determine which individual is at higher risk for developing autoimmune diseases after COVID-19 vaccination. More versatile and safer vaccines should be explored.

[Prevention of canine parvovirosis - Part 3: Vaccine-associated adverse events]

Although nowadays vaccines, especially those against canine parvovirus (CPV), are considered to be safe, vaccine-associated adverse events (VAAEs) can occur in rare cases. Some VAAEs are mild and manifest shortly (within a few days) after vaccination (e. g. gastrointestinal signs, fever, reduced general condition, lymphadenopathy). These signs are likely a result of vaccine virus replication and indicate a good immune response. Anaphylactic reactions can also occur promptly following vaccine administration and might be life threatening. Affected dogs show clinical signs such as edema, salivation, vomiting, diarrhea, hypotension, and/or shock. Since it is often unclear which component of the vaccine carries responsibility for the anaphylactic reaction it is important to limit future vaccinations of these dogs to indispensable components only. When revaccination is unavoidable, e. g. because antibodies against CPV cannot be detected, combined vaccines should not be used and CPV (and other components, if needed) should preferably be vaccinated separately. Changing the vaccine manufacturer might also prevent further anaphylactic reactions. Finally, there are VAAEs occurring after a prolonged period of time. In dogs, it is discussed that autoimmune diseases, such as immune-mediated hemolytic anemia (IMHA), can be a consequence of excessive vaccination or in the least be triggered by vaccination. Numerous dogs with IMHA are reported to have a history of receiving a vaccination within a few weeks before the onset of clinical sings. In such dogs, further vaccinations should generally be avoided.

EASL position paper on the use of COVID-19 vaccines in patients with chronic liver diseases, hepatobiliary cancer and liver transplant recipients

According to a recent World Health Organization estimate, the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic, which originated in China in 2019, has spread globally, infecting nearly 100 million people worldwide by January 2021. Patients with chronic liver diseases (CLD), particularly cirrhosis, hepatobiliary malignancies, candidates for liver transplantation, and immunosuppressed individuals after liver transplantation appear to be at increased risk of infections in general, which in turn translates into increased mortality. This is also the case for SARS-CoV-2 infection, where patients with cirrhosis, in particular, are at high risk of a severe COVID-19 course. Therefore, vaccination against various pathogens including SARS-CoV-2, administered as early as possible in patients with CLD, is an important protective measure. However, due to impaired immune responses in these patients, the immediate and long-term protective response through immunisation may be incomplete. The current SARS-CoV-2 pandemic has led to the exceptionally fast development of several vaccine candidates. A small number of these SARS-CoV-2 vaccine candidates have already undergone phase III, placebo-controlled, clinical trials in healthy individuals with proof of short-term safety, immunogenicity and efficacy. However, although regulatory agencies in the US and Europe have already approved some of these vaccines for clinical use, information on immunogenicity, duration of protection and long-term safety in patients with CLD, cirrhosis, hepatobiliary cancer and liver transplant recipients has yet to be generated. This review summarises the data on vaccine safety, immunogenicity, and efficacy in this patient population in general and discusses the implications of this knowledge on the introduction of the new SARS-CoV-2 vaccines.

Retrospective review of diphenhydramine versus diphenhydramine plus glucocorticoid for treatment of uncomplicated allergic reaction in dogs

OBJECTIVE

To report the outcome of treatment of uncomplicated allergic reactions in dogs with diphenhydramine vs diphenhydramine plus glucocorticoid and to determine the incidence rate of uncomplicated allergic reactions DESIGN: Retrospective study between January 1, 2012 and August 15, 2018.

SETTING

Privately owned, 24-hour emergency and specialty referral veterinary hospital.

ANIMALS

Eight hundred and eighty cases of dogs treated for uncomplicated allergic reaction with diphenhydramine alone or in combination with a glucocorticoid.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Two hundred ninety-nine dogs were treated with diphenhydramine alone, and 581 were treated with diphenhydramine plus Dex SP. There was no difference between the 2 groups for response to initial therapy, need for additional veterinary intervention after discharge, or persistent signs at follow-up. The cumulative incidence of emergency department presentation for uncomplicated allergic reaction in this hospital was 1.2%.

CONCLUSIONS

There was no difference in measured outcomes between dogs treated with diphenhydramine alone vs those treated with a glucocorticoid in addition to diphenhydramine in this population of dogs.

Does COVID-19 Vaccination Warrant the Classical Principle "ofelein i mi vlaptin"?

The current severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic warrants an imperative necessity for effective and safe vaccination, to restrain Coronavirus disease 2019 (COVID-19) including transmissibility, morbidity, and mortality. In this regard, intensive medical and biological research leading to the development of an arsenal of vaccines, albeit incomplete preconditioned evaluation, due to emergency. The subsequent scientific gap raises some concerns in the medical community and the general public. More specifically, the accelerated vaccine development downgraded the value of necessary pre-clinical studies to elicit medium- and long-term beneficial or harmful consequences. Previous experience and pathophysiological background of coronaviruses' infections and vaccine technologies, combined with the global vaccines' application, underlined the obligation of a cautious and qualitative approach, to illuminate potential vaccination-related adverse events. Moreover, the high SARS-CoV-2 mutation potential and the already aggregated genetical alterations provoke a rational vagueness and uncertainty concerning vaccines' efficacy against dominant strains and the respective clinical immunity. This review critically summarizes existing evidence and queries regarding SARS-CoV-2 vaccines, to motivate scientists' and clinicians' interest for an optimal, individualized, and holistic management of this unprecedented pandemic.

Antibody Response to Canine Parvovirus Vaccination in Dogs with Hypothyroidism Treated with Levothyroxine

(1) Background: No information is available on how dogs with hypothyroidism (HypoT) respond to vaccination. This study measured pre- and post-vaccination anti-canine parvovirus (CPV) antibodies in dogs with HypoT treated with levothyroxine and compared the results to those of healthy dogs. (2) Methods: Six dogs with HypoT and healthy age-matched control dogs (n = 23) were vaccinated against CPV with a modified-live vaccine. Hemagglutination inhibition was used to measure antibodies on days 0, 7, and 28. The comparison of the vaccination response of dogs with HypoT and healthy dogs were performed with univariate analysis. (3) Results: Pre-vaccination antibodies (≥10) were detected in 100% of dogs with HypoT (6/6; 95% CI: 55.7–100) and in 100% of healthy dogs (23/23; 95% CI: 83.1–100.0). A ≥4-fold titer increase was observed in none of the dogs with HypoT and in 4.3% of the healthy dogs (1/23; CI_95%: <0.01–22.7). Mild vaccine-associated adverse events (VAAEs) were detected in 33.3% of the dogs with HypoT (2/6; 95% CI: 9.3–70.4) and in 43.5% (10/23; 95% CI: 25.6–63.2) of the healthy dogs. (4) Conclusions: There was neither a significant difference in the dogs’ pre-vaccination antibodies (p = 1.000), or vaccination response (p = 0.735), nor in the occurrence of post-vaccination VAAEs (p = 0.798). The vaccination response in dogs with levothyroxine-treated HypoT seems to be similar to that of healthy dogs.

Early Life Vaccination of Companion Animal Pets

Development of the immune system of mammalian animal species parallels that of humans and involves the innate and adaptive (acquired) immune responses acting together with the thymus gland. Consequently, issues surrounding the adequacy and safety of vaccinations to protect pet animals from their relevant infectious diseases need to be addressed just as they are for humans. Pet animals, especially canines, also have unique needs because of the wide diversity of purebred and mixed breeds that vary greatly in size, type, temperament, and even maturation rates. Furthermore, pets in early life encounter a series of changes that can affect their development and induce stressors including parasite control, new homes and environment, novel foods, and the socialization that is essential at a time when vaccinations need to be given. While recognizing that this overall need is becoming more understood, current vaccination policy guidelines for companion animals are still only adhered to by about 40% of veterinarians worldwide. Clearly, vaccination of pets should no longer be considered as "one size fits all".

Adverse consequences of vaccination

The importance of adverse effects from vaccination must not be overstated. Vaccine benefits greatly exceed any risks from the procedure. Neither must they be minimized. Unnecessary vaccination must be discouraged. Hypersensitivity reactions to vaccine components are real and must be guarded against. Residual virulence, although a concern tends to be more a hypothetical than a real problem. Progressive improvements in animal vaccines have significantly reduced the chances of adverse effects occurring, although some issues persist. One such example is injection-site sarcomas in cats. Another issue is the influence of animal size on the prevalence of adverse events in dogs.

COVID-19 and cancer: A guide with suggested COVID-19 rule-out criteria to support clinical decision-making

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a highly contagious zoonotic pathogen that has exacted heavy public health, social and economic tolls. In February 2020, the World Health Organization acronymed the disease caused by SARS-CoV-2 as COVID-19, for coronavirus disease 2019. The number of confirmed COVID-19 infections, which has been detected in at least 103 countries, has reached 1,970,225 worldwide as of April 14, 2020 with 124,544 deaths, according to the U.S. Centers for Disease Control and Prevention (CDC). Many cases of COVID-19 resolve quickly. However, the disease, which, like other respiratory pathogens that cause common cold symptoms is believed to be transmitted through respiratory droplets. Infection with COVID-19 can also lead to significant morbidity and death; this is particularly the case for cancer patients. Moreover, because the signs and symptoms of COVID-19 are easily misattributed to the sequelae of cancer itself, such as pulmonary embolism, or its treatment, such as nausea and diarrhea, diagnosis may be delayed or missed. Potential COVID-19 rule out criteria, based on the Wells' criteria for pulmonary embolism, another protean disease entity, are provided as a decision-making aid. This review summarizes the current understanding of the transmission, clinical presentation, diagnosis and differential diagnosis, pathogenesis, rationale to treat the cancer or not, treatment and prevention of COVID-19 with an emphasis on implications in cancer.

Causality assessment of adverse events following immunization: the problem of multifactorial pathology

The analysis of Adverse Events Following Immunization (AEFI) is important in a balanced epidemiological evaluation of vaccines and in the issues related to national vaccine injury compensation programs. If manufacturing defects or vaccine storage and delivering errors are excluded, the majority of adverse reactions to vaccines occur as excessive or biased inflammatory and immune responses. These unwanted phenomena, occasionally severe, are associated with many different endogenous and exogenous factors, which often interact in complex ways. The confirmation or denial of the causal link between an AEFI and vaccination is determined pursuant to WHO guidelines, which propose a four-step analysis and algorithmic diagramming. The evaluation process from the onset considers all possible "other causes" that can explain the AEFI and thus exclude the role of the vaccine. Subsequently, even if there was biological plausibility and temporal compatibility for a causal association between the vaccine and the AEFI, the guidelines ask to look for any possible evidence that the vaccine could not have caused that event. Such an algorithmic method presents some concerns that are discussed here, in the light of the multifactorial nature of the inflammatory and immune pathologies induced by vaccines, including emerging knowledge of genetic susceptibility to adverse effects. It is proposed that the causality assessment could exclude a consistent association of the adverse event with the vaccine only when the presumed "other cause" is independent of an interaction with the vaccine. Furthermore, the scientific literature should be viewed not as an exclusion criterion but as a comprehensive analysis of all the evidence for or against the role of the vaccine in causing an adverse reaction. These issues are discussed in relation to the laws that, in some countries, regulate the mandatory vaccinations and the compensation for those who have suffered serious adverse effects.

Causality assessment of adverse events following immunization: the problem of multifactorial pathology

The analysis of Adverse Events Following Immunization (AEFI) is important in a balanced epidemiological evaluation of vaccines and in the issues related to vaccine injury compensation programs. The majority of adverse reactions to vaccines occur as excessive or biased inflammatory and immune responses. These unwanted phenomena, occasionally severe, are associated with many different endogenous and exogenous factors, which often interact in complex ways. The confirmation or denial of the causal link between an AEFI and vaccination is determined pursuant to WHO guidelines, which propose a four-step analysis and algorithmic diagramming. The evaluation process from the onset considers all possible "other causes" that might explain the AEFI and thus exclude the role of the vaccine. Subsequently, even if there was biological plausibility and temporal compatibility for a causal association between the vaccine and the AEFI, the guidelines ask to look for any possible evidence that the vaccine could not have caused that event. Such an algorithmic method presents several concerns that are discussed here, in the light of the multifactorial nature of the inflammatory and immune pathologies induced by vaccines, including emerging knowledge of genetic susceptibility to adverse effects. It is proposed that the causality assessment could exclude a consistent association of the adverse event with the vaccine only when the presumed "other cause" is independent of an interaction with the vaccine. Furthermore, the scientific literature should be viewed not as an exclusion criterion but as a comprehensive analysis of all the evidence for or against the role of the vaccine in causing an adverse reaction. Given these inadequacies in the evaluation of multifactorial diseases, the WHO guidelines need to be reevaluated and revised. These issues are discussed in relation to the laws that, in some countries, regulate the mandatory vaccinations and the compensation for those who have suffered serious adverse effects.