Vaccine-associated thrombocytopenia.

Vaccination is the most cost-effective means of preventing and even eliminating infectious diseases. However, adverse reactions after vaccination are inevitable. In addition to common vaccine-related adverse reactions, some rare but serious adverse reactions have been reported, including secondary immune thrombocytopenia (ITP). The measles-mumps-rubella (MMR) vaccine is currently the only vaccine for which a cause-effect relationship with immune thrombocytopenia has been demonstrated with an incidence of approximately 0.087-4 per 100,000 doses, and the complication is mostly observed in children. In addition, thrombocytopenia can be induced by coronavirus disease 2019 (COVID-19) vaccines following COVID-19 vaccination primarily occurs within a few weeks post-vaccination. The condition mostly occurs in elderly individuals with no sex differences. Its incidence is approximately 0.80 to 11.3 per million doses. Some patients have previously suffered from chronic ITP likely to develop exacerbation of ITP after COVID-19 vaccines, especially those who have undergone splenectomy or are being treated with >5 medications. Based on clinical practice, first-line treatments for vaccine-associated thrombocytopenia are essentially limited to those used for primary ITP, including glucocorticoids and intravenous immunoglobulin (IVIg).

Epidemiological features and risk factors for measles and rubella in Taiwan during 2011 to 2020.

The risk of geographic transmission of infectious diseases due to air travel varies greatly. Our aim is to survey empirical data that provide a retrospective historical perspective on measles and rubella. This study used the open data website provided by the Taiwan Centers for Disease Control (TCDC) to extract the reported numbers of measles and rubella case between 2011 and 2020. There were 306 cases of measles and 135 cases of rubella. The incidence of measles and rubella per million population were 0 to 6.0 and 0 to 2.6, respectively. There was a gradual increase in the numbers of cases in those aged 20-39 years, and distinct duration patterns. It indicated that the risk of contracting rubella has significantly decreased in the last 5 years. Measles cases aged 20 to 39 years accounted for 72.5% of all cases. Rubella cases aged 20 to 39 years accounted for 59.3% of all cases. The male and residency in the Taipei metropolitan area or northern area were identified as potential risk factors for measles and rubella. Coverage with the first dose of the measles, mumps and rubella (MMR) vaccine in Taiwan increased from 97.31% to 98.86%, and the uptake rate of the second dose of the MMR vaccine increased from 95.73% to 98.39% between 2010 and 2020. Furthermore, the numbers of imported cases of measles (n = 0) and rubella (n = 0) reported during the coronavirus disease 2019 (COVID-19) pandemic were lower than those from 2011 to 2019. Measles and rubella cases were imported most frequently from Cambodia and Vietnam. This study represents the first report of confirmed cases of acquired measles and rubella from surveillance data of the TCDC between 2011 and 2020, also demonstrates that the numbers of cases of measles and rubella significantly decreased in Taiwan during the COVID-19 pandemic.

Anaphylaxis rates associated with COVID-19 vaccines are comparable to those of other vaccines.

We retrieved data on 8940 anaphylaxis cases post-COVID-19 vaccination from the US Vaccine Adverse Event Reporting System and the European EudraVigilance from week 52/2020 through week 31/2021 and compared them with those of other vaccines. Overall, 837,830,000 COVID-19 vaccine doses were delivered in the US and Europe during the study period, for which the vaccine name was known. The mean anaphylaxis rate was estimated at 10.67 cases per 106 doses of COVID-19 vaccines (range: 7.99-19.39 cases per 106 doses depending on the vaccine). COVID-19 vaccines ranked fifth in reported anaphylaxis rates, behind rabies, tick-borne encephalitis, measles-mumps-rubella-varicella, and human papillomavirus vaccines (70.77, 20, 19.8, and 13.65 cases per 106 vaccine doses, respectively). COVID-19 vaccines are within the range of anaphylaxis rates reported across several common vaccines in these two passive reporting systems. These data should be communicated to reassure the general population about the safety profile of COVID-19 vaccines.

Vaccine Videos and Information Sharing: The Effects of Framing, Evidence Type, and Speaker Expertise.

YouTube videos have been used to inform and misinform the public about the safety of vaccines related to health threats such as measles and COVID-19. Understanding how such videos can promote the sharing of accurate vaccine safety information is of the utmost importance if health researchers are to combat the spread of misinformation and encourage widespread uptake of vaccines. Through the lens of prospect theory, this study conducted a 2 (framing: loss v. gain) x 2 (evidence type: episodic v. thematic) x 2 (speaker expertise: expert v. non-expert) between-subject factorial experiment in which a sample of N = 400 US adults over the age of 18 recruited through MTurk were asked their intention to share vaccine safety information with others after watching a manipulated YouTube video. The results showed that loss framing was associated with perceived MMR severity which was, in turn, associated with the likelihood that participants would share MMR vaccine information with others, via any means. However, this process varied depending on the type of evidence delivered, and the expertise of the speaker. Results and limitations are discussed in the context of vaccine communication and social media.

Neurologic Safety Monitoring of COVID-19 Vaccines: Lessons From the Past to Inform the Present.

The spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has triggered a global effort to rapidly develop and deploy effective and safe coronavirus disease 2019 (COVID-19) vaccinations. Vaccination has been one of the most effective medical interventions in human history, although potential safety risks of novel vaccines must be monitored, identified, and quantified. Adverse events must be carefully assessed to define whether they are causally associated with vaccination or coincidence. Neurologic adverse events following immunizations are overall rare but with significant morbidity and mortality when they occur. Here, we review neurologic conditions seen in the context of prior vaccinations and the current data to date on select COVID-19 vaccines including mRNA vaccines and the adenovirus-vector COVID-19 vaccines, ChAdOx1 nCOV-19 (AstraZeneca) and Ad26.COV2.S Johnson & Johnson (Janssen/J&J).

Safety of vaccines used for routine immunization in the United States: An updated systematic review and meta-analysis.

BACKGROUND: Understanding the safety of vaccines is critical to inform decisions about vaccination. Our objective was to conduct a systematic review of the safety of vaccines recommended for children, adults, and pregnant women in the United States. METHODS: We searched the literature in November 2020 to update a 2014 Agency for Healthcare Research and Quality review by integrating newly available data. Studies of vaccines that used a comparator and reported the presence or absence of key adverse events were eligible. Adhering to Evidence-based Practice Center methodology, we assessed the strength of evidence (SoE) for all evidence statements. The systematic review is registered in PROSPERO (CRD42020180089). RESULTS: Of 56,603 reviewed citations, 338 studies reported in 518 publications met inclusion criteria. For children, SoE was high for no increased risk of autism following measles, mumps, and rubella (MMR) vaccine. SoE was high for increased risk of febrile seizures with MMR. There was no evidence of increased risk of  intussusception with rotavirus vaccine at the latest follow-up (moderate SoE), nor of diabetes (high SoE). There was no evidence of increased risk or insufficient evidence for key adverse events for newer vaccines such as 9-valent human papillomavirus and meningococcal B vaccines. For adults, there was no evidence of increased risk (varied SoE) or insufficient evidence for key adverse events for the new adjuvanted inactivated influenza vaccine and recombinant adjuvanted zoster vaccine. We found no evidence of increased risk (varied SoE) for key adverse events among pregnant women following tetanus, diphtheria, and acellular pertussis vaccine, including stillbirth (moderate SoE). CONCLUSIONS: Across a large body of research we found few associations of vaccines and serious key adverse events; however, rare events are challenging to study. Any adverse events should be weighed against the protective benefits that vaccines provide.