Covid vaccine dose mix match

On June 29, a nurse will prepare an injection of Comirnaty vaccine at an outdoor vaccination center set up by the French Red Cross on Place de la République in Paris. — Agence France-Presse / Martin Bureau

Science needs to tell the truth exactly, and it does. This is the difference between science and art. In science, there is no room for accepting things without testing and checking. As scientists, we oblige the scientific community, at least those enlightened, to know the facts and numbers in a timely manner in order to adopt or modify the correct course.

Combined and mixed with Covid vaccine

GAVI found impressive evidence that the immune response was stronger after mixing vaccine shots from different manufacturers compared to two doses of the same vaccine. The GAVI statement states: ‘If the virus mutates the target area of ​​the vaccine, the effectiveness of the vaccine may be reduced. But if the two vaccines target different parts of the virus, it gives our immune system multiple weapons in its arsenal.

European countries, including France and Germany, have recently recommended the Pfizer-BioNTech vaccine Comirnaty as a second dose to those who first received the AstraZeneca vaccine. This was prompted after the first dose of the AstraZeneca vaccine, now registered as Vaxzevria (as Covishield in India), showed that many young people were oozing blood from the capillaries of the body. Readers may know that this side effect is in addition to blood coagulation in larger blood vessels, which was previously reported as a side effect of the vaccine. Several countries, including Canada and Spain, have already approved dose mixes due to concerns about this rare but potentially fatal blood clot, primarily related to vaccines. The Canadian decision will be made after the National Advisory Board on Immunization recommends that the second Covid vaccine be given with vaccines from different sources. This decision was made after Australian and foreign regulators concluded that Vaxzevria was likely to be the cause of a rare side effect called thrombosis with thrombocytopenia.

Australia and European countries (Germany, Sweden, Norway, Denmark) and South Korea now allow Vaxzevria to people over the age of 60. Meanwhile, Comirnaty and another mRNA vaccine, Moderna’s, are currently registered as Spikevax and have been shown to cause carditis or heart inflammation in a small number of children under the age of 18 after vaccination. Therefore, Professor Robert Dingwall, a member of the UK’s Joint Committee on Immunization and Immunization, said that innate immunity caused by infections, rather than asking children to take the “potential” risk of vaccines. Better protection by. ” However, this does not mean that the same thing will happen in Bangladesh. A country’s epidemiological profile and individual response to a vaccine are determined by race and individual genetic makeup and are an important factor in the difference in response to a vaccine. But to assess it, and in fact, for vaccines on the subject, Bangladesh needs to outsource strong post-vaccination surveillance, a functional pharmacovigilance system. The traction of the vaccine business should not be lost to us. Similarly, the government should be urged to establish and use the ability to assess the efficacy of the various vaccines used or used.

Spanish study

In April, a study called the CombivacS study in Spain enrolled 673 healthy people aged 18-60 years across five hospitals. Of these, 441 were evenly divided by gender. These people had previously received a single dose of Vaxzevria, were randomly selected, and received Comirnaty at least 8 weeks after the first dose. They were from New York City, USA and Mainz, Germany. Prior to receiving the booster, a control group of 232 people was selected. The study was led by the Charles III Institute of Health in Madrid. Magdalena Campins, a researcher at the CombivacS study at Valdebron University Hospital in Barcelona, ​​Spain, said participants began producing much higher levels of antibodies than before, and these antibodies produced SARS-CoV-2. In a clinical test, he reported that he was able to recognize and inactivate. Control participants who did not receive booster vaccination did not experience any changes in antibody levels.

In fact, antibody levels were about 40 times higher than those who received Comirnaty after 14 days compared to participants who received a single shot of Vaxzevria. Neutralizing antibodies that repel the virus were boosted more than 7-fold higher after administration of Comirnaty Shot. This is higher than described elsewhere where the same vaccine was given twice. However, this study does not directly compare the vaccine with two doses of the Vaxzevria combination. The most common adverse events of heterologous vaccines were headache (44%), malaise (41%), chills (25%), nausea (11%) and cough (7%).

British studies

The latest UK-based recommendations for mix and match were based on data from four studies. In Phase II (CoM-CoV) of the ongoing study, 830 people received either the Vaxzevria or Cominatry prime vaccine, followed by the same or alternative vaccine as booster immunization. The dosing schedule was 28 or 84 days. The primary endpoint was the production of anti-spiked antibodies, which showed better mix-and-match production. Hematological and biochemical profiles are similar between heterologous (combination vaccine) and allogeneic (same vaccine) schedules, and all laboratory hazards of grade 2 or lower on heterologous vaccine schedules, including influenza-like symptoms. There were events, but none of the groups had thrombocytopenia. 7 post boost. The side effects were short-lived and were effectively treated with Paracetomol. However, this result is from people over the age of 50. It is believed that side effects can be more pronounced among young people. Researchers at Oxford University are currently investigating whether a 12-week dosing interval reduces side effects.

German studies

A new preprint study from Germany shows that the combination of Vaxzevria and Cominatry is immunologically superior to the former two doses. Mixing produces significantly higher amounts of anti-spiking antibodies and increases neutralizing activity against alpha, beta, and gamma mutants. Both beta and gamma variants carry mutations that can evade vaccine-induced immunity, increasing the risk of SARS-CoV-2 epidemic, severe illness, and death. The second dose of the community vaccine increased anti-spiked protein IgG antibody levels by a 11.5-fold compared to the 2.9-fold increase observed in those who received the second dose of Vaxzevria. Increased levels of the anti-peplomer IgA antibody have also been observed, suggesting a better humoral (antibody-based) immune response at mixed match doses. Two doses of Vaxzevria showed some immune response to the alpha variant, but had no effect on the other two variants. The second community dose increased neutralizing antibodies against all of the mutant strains of concern. However, even if the Vaxzevria-Cominatry group showed the highest neutralization response to the Wuhan strain, followed by the alpha mutant, the mixmatch dose was still inefficient for the beta and gamma mutants. A mix-and-match efficiency test for delta variants is awaited.

Peplomer-specific B cells, the white blood cells that produce antibodies, increased significantly on a mix-and-match schedule. An increase in B cell isotype switch, IgD to IgM antibody type, was observed in people who received Cominatry as the second dose. There are also spike protein-specific CD4 molecules that carry T lymphocytes, white blood cells that direct B cells to produce antibodies, and spike protein-specific gamma interferon (a protein that stimulates cells to prevent viral replication) called cytokines. It has increased significantly. Mixed match group. The Vaxzevria priming (first dose) immune response was monitored before and 3 weeks after booster immunization with Vaxzevria or Cominatry. While both vaccines enhanced prime-induced immunity, the latter induced a significantly higher frequency of spike-specific CD4 and CD8-T lymphocytes called cytotoxic T cells, destroying infected cells in the body. , In particular, the three “variants of concern” above.

Mixed doses of different vaccines are not new. After the 2014 Ebola hemorrhagic fever epidemic, Johnson End Johnson was able to produce a double-dose vaccine containing different carrier viral vectors (modified versions of adenovirus and poxvirus) to provide long-term immunity. It was. Mixing and matching Covid vaccines may solve the vaccine shortage problem in countries that are struggling to supply. At bargains, it will also boost the body’s immunity to viral variants.

Second booster or third dose

Scientists in the United States and the United Kingdom have begun booster shot trials to assess the effect of another jab on fully vaccinated people. This could be a routine within September or a year from this fall. Thailand is also considering starting a third dose to recipients of coronabac and baczebria among medical professionals and people with comorbidities.

Participants in the study will be given booster shots of the Spikevax vaccine — whether they have previously received two shots of the mRNA vaccine (from Cominatry or Spikevax) or Jansen shots since these vaccines — [AstraZeneca] J & J — Based on a very similar platform, you can predict that the results for the Delta variant will be at least similar and probably even better, and make reasonable assumptions. The booster dose of Spikevax was reported to have similar side effects on the second Cominatry shot, but the third was a bit more serious.

Baylor College of Medicine virologist Joseph Hyser was fully vaccinated at Cominatry at the end of January. Still, when he received an email in May asking if he was interested in getting a third booster shot at Spikevax, he immediately signed up and gave him a third dose. However, he suffered slightly more side effects with Spikevax than his previous shots.

Researchers at Johns Hopkins University advise that people with weakened immunity should be given a third dose to boost their immunity, regardless of the vaccine they had previously received. The Dominican Republic unconditionally offers a third vaccine if the previous vaccine was Coronavac’s Vaxzevria. The United Arab Emirates and Bahrain are providing booster shots of the Sinopharm vaccine to residents and citizens more than six months after the second vaccination.

In all of this, Western scientists and the Western media have not brought Russian and Chinese vaccines into their discourse as an alternative or booster to Western vaccines, or vice versa.

AM Zakir Hussain is a former director of primary health care and disease management, a former director of IEDCR and DGHS, a former regional advisor to SEARO and WHO, and a former staff consultant to the Asian Development Bank in Bangladesh.