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COVID-19 Vaccine Updates
With input from Dr Monica Vasudev
1308: CDC and Pfizer are probing the death of a very healthy Miami obstetrician 16 days after receiving the vaccine who suffered a brain haemorrhage.
- Gregory Michael, aged 56, died on January 3, 16 days after he was administered the Pfizer COVID-19 vaccine. His wife Heidi Neckelmann said that he was very healthy before receiving the shot.
- He succumbed to a stroke caused by acute idiopathic thrombocytopenic purpura (ITP), a blood disorder caused by a lack of platelets.
- The death is being investigated by Pfizer and the Florida Department of Health and the federal Centers for Disease Control and Prevention.
- Heidi has insisted that Michael did not have an immune disorder or any similar condition that could have led to ITP.
- It must be noted that serious adverse events, including deaths that are unrelated to the vaccine, are likely to occur at a similar rate as in the general population.
- Samples from an autopsy have been sent to the CDC, stated Darren Caprara, director of operations for the Miami-Dade County Medical Examiner Department.
Immune thrombocytopenia, often known as immune thrombocytopenic purpura (ITP), as an important complication of COVID-19
Forty five cases of new-onset ITP in COVID-19 patients have described in literature till date. Majority of the cases (71%) have been reported in the elderly (> 50 years) and 75% cases had moderate-to-severe COVID-19. Three cases (7%) have been reported in the pediatric age group. Reports of ITP in asymptomatic COVID-19 patients (7%) emphasize the need for COVID-19 testing in newly diagnosed patients with ITP regardless of COVID-19 symptoms during the pandemic. ITP onset was reported in 20% cases 3 weeks after onset of COVID-19 symptoms, with several reports after clinical recovery. SARS-CoV-2-mediated immune thrombocytopenia can be attributed to the underlying immune dysregulation.
ITP is associated with several types of vaccinations
In previous studies, the risk of developing ITP increased after administration of measles-mumps-rubella (MMR), some together with MMR, hepatitis A, varicella, and diphtheria-tetanus-pertussis vaccines in children and adolescents. Adjuvants, which are compounds incorporated into vaccines to improve immunogenicity, have been linked with autoimmune/inflammatory syndrome induced by adjuvants. The association between ITP and influenza vaccination is still not clear.
ITP has been described following vaccinations against various infectious agents, such as MMR, Haemophilus influenza, hepatitis B virus, human papilloma virus, varicella-zoster, diphteria-tetanus-acellular pertussis (DTap), polio, and pneumococcus.
(Source: https://www.dailymail.co.uk/; SN Compr Clin Med. 2020 Sep 19;1-11; Immunol Res. 2013 Jul;56(2-3):299-303; International Journal of Infectious Diseases 99 (2020) 243–244)
1309: Cloth Masks Provide Inferior Protection vs. Medical Masks
- Cloth masks must not be considered equivalent to medical masks for the prevention of COVID-19 in clinical settings, suggests a review published in Annals of Family Medicine by Ariel Kiyomi Daoud, a researcher at the University of Colorado at Denver, Aurora.
- Cloth masks may provide only some degree of protection. If clinicians use cloth masks, the fit, material, and number of layers must be considered. If cloth masks are used as a last resort, additional measures such as pairing cloth masks with plastic face shields may be helpful.
- Go for frequent cloth mask changes in order to reduce the risk of moisture retention and washing according to hospital laundry standards.
- Cloth materials prevent some level of penetration, but usually have lesser filtration efficiency and greater variability in comparison with medical masks. Materials with the greatest filtration efficacy – vacuum bags and tea towels — appeared to have low airflow, which limits their use.
- Two studies noted that additional layers may increase the viral filtration efficacy of cloth masks.
- Three or more layers of cloth may reduce the spread of droplets and aerosols from the wearers. Cloth masks, therefore, may be used in community settings to prevent the spread of infections from the sick, especially the asymptomatic individuals.
- Cloth masks may be used by healthcare workers as a last resort, if there is no other option and in that case, they should have at least three layers, fit to the face, and must be washed regularly.
1310: Interim analysis of early trial suggests COVID-19 vaccine Ad26.COV2.S safe and immunogenic
An interim analysis of phase 1–2a trial, published in The New England Journal of Medicine, suggests that COVID-19 vaccine candidate Ad26.COV2.S had an acceptable safety and reactogenicity profile and was found to be immunogenic after a single vaccination with either the low or high dose in both younger and older adults.
The trial, conducted at 12 centres in Belgium and the United States, randomized 805 healthy adults aged 18 to 55 years (n=402) and 65 years or older (n=403) to receive the Ad26.COV2.S vaccine at a dose of either 5×1010 viral particles (low dose) or 1×1011 viral particles (high dose) per mililitre or placebo, given intramuscularly, in a single-dose or two-dose schedule, at a gap of 56 days. The primary end points included the safety and reactogenicity of each dose schedule.
Following the administration of the first vaccine dose in both cohorts and after the second dose among participants aged 18 to 55 years, the most frequent solicited adverse events included fatigue, headache, myalgia, and injection-site pain. The most frequent systemic adverse event was fever. Systemic adverse events appeared less commonly in participants aged 65 or older and in those administered the low vaccine dose.
Local and systemic reactions occurred on the day of immunization or the next day and generally resolved within 24 hours. The systemic reactions responded to antipyretic drugs, and there was no need for the prophylactic use of such drugs.
After the second dose in the 18 to 55 year age group, the incidence of grade 3 solicited systemic adverse events was much lower than that after the first immunization in both the low-dose and high-dose groups. The finding contrasts with observations with respect to messenger RNA-based vaccines, for which the second dose has been associated with increased reactogenicity.
Neutralizing-antibody titres against wild-type virus were identified in 90% or more of all participants on day 29 after the first dose and reached 100% by day 57, with a further rise in titres, irrespective of vaccine dose or age group. The titres remained stable until at least day 71. A second dose provided an increase in the titre by a factor of 2.6 to 2.9.
Spike-binding antibody responses appeared to be similar to neutralizing-antibody responses. On day 14, CD4+ T-cell responses were detected in 76% to 83% of the participants in the 18-55 year age group and in 60% to 67% of those aged 65 or older, with a clear skewing toward type 1 helper T cells. Among those in the 18 -55 age group, CD8+ T-cell responses were identified in 51% of those in the low-dose group and in 64% in the high-dose group. Among the 65 or older age group, CD8+ T-cell responses had a lower incidence of 36% in the low-dose group and 24% in the high-dose group.
All ongoing phase 3 trials of other COVID-19 vaccines have evaluated two-dose schedules. A single dose of Ad26.COV2.S exhibited a strong humoral response in a majority of recipients, with the presence of S-binding and neutralizing antibodies in over 90% of the participants, regardless of either age group or vaccine dose, noted Jerald Sadoff, MD, Janssen Vaccines and Prevention, Leiden, the Netherlands, and colleagues. Furthermore, during 71 days of follow-up after the first dose, antibody titres increased and stabilized, thus highlighting the durability of the Ad26.COV2.S-elicited immune response.
(SOURCE: The New England Journal of Medicine; DG Alert)
Dr KK Aggarwal
President CMAAO, HCFI and Past National President IMA