Successful Vaccination Strategy in the UK: Why Astrogeneka Reduces Levels Between 8-12 Weeks

On December 30, 2020, the MHRA (UK Healthcare and Medicine Products Regulation Agency) approved the Oxford-Astrogeneca vaccine, with the second dose being given 3 months after the first dose. A similar procedure was approved for the Pfizer Bioentech vaccine (which was approved on December 2). The reason given by the government is the need for an even distribution of vaccines: Vaccinate more than twice as many people with (some) available vaccines.

This decision took many by surprise I decided to go to the sources and re-read the Oxford-Astrogeneca Phase III vaccine study (Published At the Lancet on December 8). There I was able to confirm that the MHRA result was correct: for reasons of dose delivery during trials conducted in the UK, Brazil and South Africa, not all test volunteers received a second dose within 4 weeks of the first dose. Therefore, it became clear in Table 3 of the work Efficacy was 65.6% when the second dose was given 6 to 12 weeks after the first dose. However It was reduced to 53.4% ​​when the second dose was given 6 weeks before the first dose.

Kent, the UK variant (p.117) is also more infectious and a little more deadly, more aggressive, but vaccines work. The point is, with the Manas variant having the E484K mutation, the vaccine will not work, which is very ineffective., Which is an important feature. In this way, Oxford is developing a new vaccine to change it to include these new varieties. But it will only be ready in October, Because you have to go back to the lab stage.

The important thing to note is that this mutation appeared a few weeks ago in various places around the world, in South Africa, the United Kingdom, Brazil and New York. When they arise in different places, It may be the natural evolution of the SARS-CoV-2 virus to obtain these mutations. In Argentina, if there are multiple infections, a local variant may be imaginary, with some of these mutations. It is not known whether the ceiling of these mutations has been reached, or whether the virus can continue to develop.

Given the current shortage of vaccines, can one think of using a single dose in the case of the Oxford Astrogenica vaccine? It is not recognized. I would be irresponsible to raise it. What was done here in the UK: X was the size of millions, it was said Because not everyone had two doses, the population was doubled in January, with the second dose being used 8 to 12 weeks later, i.e. three months after the last injection.. Immunity is even better during this period if the second dose is used after the first period.

It would be very effective to put a second dose of Oxford AstraZeneca in between. When the second dose is given four weeks later, the final immunity is 53.4%, whereas if used between 8 and 12 weeks, Rises by more than 80%. This is an important part of the information. When a person has maximum immunity 22 days after the first dose, it remains stable at 72% efficacy for 3 months or 12 weeks. No one in the UK talks about using a single dose.

Here this method was implemented on December 30: 8 to 12 weeks between doses. This gives a 3-month grace period and increases the distribution of vaccines (here Instead of vaccinating 13 million people, they vaccinated 26 million) Because the vaccine is given to everyone for that period The cases were able to be significantly reduced. According to this study, immunocompromised individuals have no serious complications, have not been hospitalized, and have not died from COVID-19.. For example there were positives among the medical staff, but they only had one headache.

Because there are fewer infections, the chances of mutations for the more aggressive strains are lower. In addition, this is important because they took this dose divided by 3 months with a strict plan of the target population they prioritized.

Established by the MHRA UK Joint Committee on Vaccines and Immunization (JCVI) with MHRA approval of vaccines (with Oxford Astrogenica and Pfizer BioNtech 3 months apart) The 4 priority orders of people at risk are to be vaccinated first:

People over the age of 80 and their assistants in nursing homes

Adults over 80 years of age + first tier health and social service workers

People over 75 (and other health workers)

People over 70, people with disabilities (including people with disabilities and their assistants).

March 6, 2021, Valuable Lancet Magazine General A study and accompanying comment Analyzed the results of the Oxford Astrogeneca vaccine being given in the UK between two doses with an interval of 12 weeks. The study determined the effectiveness of this method: 22 days after the first dose, 76% of those vaccinated acquired immunity, which was stable for 3 months. After the second dose, immunity increased to 81.3% (compared to 53.4% ​​when the second dose was 6 weeks ago). One fact that needs to be highlighted is that COVID-19 was not hospitalized 21 days after the first dose. This shows the ingenuity of the community to be vaccinated with 1 dose as the number of cases has dropped significantly: from 68,053 daily infections on January 8 to 5,758 new cases on March 17, from 1890 deaths in January to 141 deaths on March 17.

In 3 months, 27 million people have been vaccinated, most with 1 dose (Only 1.7 million with two sizes), which represents 38% of adults. Cases, hospitalizations and deaths were significantly reduced by 80%.

Recently, I attended a seminar with a professor Sharon Peacock, Scientific Adviser to the Prime Minister Boris Johnson, Where it is provided: “COVID-19 mutations: past, present and future”. Two comments affected me significantly:

1- The virus weakens in the elderly because they have a weakened immune system. SARS-CoV-2’s RNA (“virus multiplication machines”) are defective, so there are many “replication errors” (mutations) as the virus multiplies, with significantly higher potential for new variants (highly infectious / dangerous). It also occurs in other organisms with weakened immune systems, i.e. those with priority / defects. It happened in Kent, on September 20 the British variant (p.117) appeared in an elderly man with a weakened immune system. From this it is these people who should get the benefit of vaccination (in addition to 1st line health workers). Young people are significantly less likely to develop a new variant (strain) of infection because the immune system is naturally strong in them (for this reason the vaccination preference system was implemented in the UK).

2- The variant that appeared in Manas is characterized by the E484K mutation, which makes the virus more aggressive and more contagious.. An important fact is that current vaccines are not very effective against E484K (they are being modified to cover variants with this mutation, and will be modified in October at the Oxford-Astrogeneneca). This variation has also arisen spontaneously in South Africa, New York and Bristol. This suggests that getting the E484K mutation may be a natural evolution of the virus. Therefore, if epidemics occur in the population, it may arise spontaneously anywhere. The strategic importance then arises to vaccinate a large number of people quickly, reducing infections and thus minimizing the possibility of mutations and new variants.

The comments above (1 and 2) support the need to modify vaccination practices: Offer vaccine for administration of two doses and the elderly with an interval of 8 to 12 weeks, People with disabilities, the disabled, their caregivers and front line health workers.

The author, Marta Cohen, is a pediatrician from Argentina – Origin from La Plata – who currently works at Sheffield Children’s Hospital in the United Kingdom. He was distinguished by the Order of the Empire by the British Royalist because of his work of more than a decade specializing in the investigation of sudden death of infants.