| Sohu Health
Author | Zhou Yichuan
Edited by | Wu Shinan
In late June, German Chancellor Merkel received the Moderna vaccine two months after receiving the AstraZeneca COVID-19 vaccine. The mixed vaccination strategy was supported by Germany, Dominican , Canada and other countries. Is this strategy really effective? CNN website published an article pointing out that mixed vaccination can alleviate the current situation of tight vaccine supply in many regions around the world, but more real-world data needs to be confirmed whether it is effective.
Last week, the German Vaccination Standing Committee launched a study saying that a hybrid vaccination strategy can produce very significant immunization effects. Therefore, regardless of age, people who receive the first dose of AstraZeneca vaccine in their country should receive the mRNA vaccine, namely Pfizer /BioNTech vaccine or Moderna vaccine.
Dominican Republic is promoting the Pfizer vaccine, AstraZeneca vaccine and Sinovac vaccine. The country requires medical personnel to receive a third dose of vaccine of a different type from the first two doses to fight the emerging coronavirus variant. The Canadian National Immunization Advisory Committee recommends that people who have received one dose of AstraZeneca vaccine should be best used to immunize mRNA vaccine as a second dose of the vaccine.
UK research shows that the AstraZeneca vaccine and the Pfizer vaccine can produce a strong immune response after being vaccinated, but the immune effect of using the Pfizer vaccine alone is stronger. Meanwhile, a Lancet study confirmed that mixed vaccination may bring more mild side effects, including fever, chills, fatigue and headaches. These side effects are short-lived and there are no other safety issues.
European Medicines Agency (EMA) said that the agency did not recommend the combination of two different types of vaccines, but there is indeed some scientific basis. Preliminary research results from Spain and Germany confirm that this strategy can produce satisfactory results without safety concerns.
Of course, because the AstraZeneca vaccine has the side effects of potential fatal coagulation events in young groups, some countries mainly adopt a mixed vaccination strategy for safety reasons rather than efficacy. For example, Spain recommends that adults under 60 years old should receive mRNA vaccine after receiving AstraZeneca vaccine to avoid the risk of side effects.
Dr. Amesh Adalja, a Center for Health and Safety at Johns Hopkins University, analyzed that mixed vaccination is also known as heterologous primary promotion vaccination. The immune system has different immune responses to different types of vaccine technologies. After thoroughly studying its mechanism, a better vaccine plan can be designed, especially to provide further assistance to organ transplanters and other organ transplanters with poor immunity and poor response to standard treatment plans.
Since the vaccine was launched, many studies have been exploring the immune effects of mixed vaccination with different types of vaccines. Even before the COVID-19 epidemic, some people tried avian influenza virus . We cannot predict whether the COVID-19 epidemic will end in a few months or years. On the one hand, we must invent further second-generation vaccines based on the current basis, and on the other hand, we can use this strategy to improve and upgrade vaccines for other diseases.
Although multiple countries have introduced recommendations for mixed vaccination, the United States has no relevant vaccination plans. At present, the United States is likely to usher in another round of attacks on the new coronavirus Delta variant, and some people are worried about whether they need to step up vaccination. Dr. Paul Offit, an American immunology expert and director of the Center for Vaccine Education at Children's Hospital in Philadelphia, stressed that the United States does not need to strengthen vaccination at this time. Vaccination strategies should be driven by scientific guidance, and current data prove that two doses of mRNA vaccine or one dose of Johnson & Johnson vaccine can protect people from severe infections of delta mutant virus .
Reference:
1.CNN
More places are mixing vaccines, but do they need to?
https://edition.cnn.com/2021/07/02/health/mixing-coronavirus-vaccines-explainer-wellness/index.html
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