Expert review of vaccines
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Expert review of vaccines · Aug 2021
ReviewCOVID-19 vaccines: concerns beyond protective efficacy and safety.
Several vaccine candidates have been developed using different platforms, including nucleic acids (DNA and RNA), viral vectors (replicating and non-replicating), virus-like particles, peptide-based, recombinant proteins, live attenuated, and inactivated virus modalities. Although many of these vaccines are undergoing pre-clinical trials, several large clinical trials investigating the clinical efficacy and safety of coronavirus disease 2019 (COVID-19) vaccines have produced promising findings. ⋯ What is the context?Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) caused a global pandemic: the coronavirus disease 2019 (COVID-19) outbreak. The development and implementation of the COVID-19 vaccine could be an important measure to control the COVID-19 pandemic.What is new?Several phase 3 clinical trials have demonstrated the effectiveness and safety of COVID-19 vaccines for the prevention of SARS-CoV-2 infections. Several COVID-19 vaccines have obtained emergency use authorization and been implemented in many countries. Although concerns regarding unusual blood clots and low platelet counts have been raised, the benefits of COVID-19 vaccines outweigh the potential risks of adverse events.What is the impact?Except for children, the COVID-19 vaccine is recommended for all people, including those pregnant or immunocompromised. Healthcare authorities should advise people receiving the vaccine that they must seek medical attention if they have associated thromboembolism and thrombocytopenia symptoms. More studies are necessary to determine the appropriate vaccine dose and regimen strategy, as well as the effectiveness of COVID-19 vaccines against variants of concerns. A global effort must be made to achieve widespread vaccination and herd immunity.
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Expert review of vaccines · Aug 2021
ReviewCOVID-19 vaccines and thrombosis with thrombocytopenia syndrome.
To combat COVID-19, scientists all over the world have expedited the process of vaccine development. Although interim analyses of clinical trials have demonstrated the efficacy and safety of COVID-19 vaccines, a serious but rare adverse event, thrombosis with thrombocytopenia syndrome (TTS), has been reported following COVID-19 vaccination. ⋯ What is the context?Thrombosis with thrombocytopenia syndrome (TTS) usually develops within 2 weeks of the first doses of the ChAdOx1 nCoV-19 and Ad26.COV2.S COVID-19 vaccines.TTS mainly occurs in patients aged < 55 years and is associated with high morbidity and mortality.What is new?TTS mimics autoimmune heparin-induced thrombocytopenia and can be mediated by platelet-activating antibodies against platelet factor 4. Non-heparin anticoagulants, such as fondaparinux, argatroban, or a direct oral anticoagulant (e.g. apixaban or rivaroxaban) should be considered as the treatment of choice if the platelet count is > 50 × 109/L and there is no serious bleeding. Intravenous immunoglobulins and glucocorticoids may help increase the platelet count within days and reduce the risk of hemorrhagic transformation when anticoagulation is initiated.What is the impact?TTS should be a serious concern during the implementation of mass COVID-19 vaccination, and patients should be educated about this complication along with its symptoms such as severe headache, blurred vision, seizure, severe and persistent abdominal pain, painful swelling of the lower leg, and chest pain or dyspnea. The incidence of TTS is low; therefore, maintenance of high vaccination coverage against COVID-19 should be continued.
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Expert review of vaccines · Jul 2021
Expert opinion on the way forward for improving maternal influenza vaccination in India.
: Rates of maternal vaccination against influenza are extremely low in India. An expert panel of obstetric-gynecologists and pediatricians met to develop consensus-based recommendations for improving awareness of the benefits of influenza vaccination during pregnancy in India. ⋯ : Although clinical evidence demonstrates the benefit of maternal influenza vaccination in any trimester, influenza vaccination is not widely accepted in India as an integral part of antenatal care. There is a lack of familiarity among obstetricians of clinical guidelines on maternal influenza vaccination. This can be addressed with an education campaign targeting obstetricians and other providers of maternal healthcare. With variable influenza seasons between regions in India, common vaccine stock shortages, and data suggesting influenza vaccination is feasible anytime in pregnancy, all opportunities to offer vaccination to this high-risk group for severe influenza disease should be considered.
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Expert review of vaccines · Apr 2021
ReviewEffects of SARS-CoV-2 variants on vaccine efficacy and response strategies.
As the global severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic continues to spread, several variants have emerged. Variants B.1.1.7 and B.1.351 have attracted significant attention owing to their widespread transmission and possible immune evasion. A total of 19 SARS-CoV-2 vaccines based on original strains have entered clinical studies, including nine vaccines that have obtained emergency use or conditional marketing authorizations. However, newly emerging variants may affect their protective efficacy. Decreased efficacy of the Novartis, Johnson & Johnson, and AstraZeneca vaccines against B.1.351 has been reported. The spread of variants creates a tremendous challenge for the prevention and control of the SARS-CoV-2 pandemic via vaccination. Several response strategies, including accelerating massive rollouts of current vaccines, increasing vaccine immunogenicity by increasing vaccination doses, and accelerating next-generation vaccines against variants, have been suggested. ⋯ Current SARS-CoV-2 vaccines authorized for emergency use or under clinical trials have shown certain advantages in providing adequate protection against new variants. We analyzed the effects of reported variants on neutralizing antibodies and the protective efficacy of different vaccines and propose strategies for applying current vaccines against variants and developing next-generation vaccines.