Vaccines against COVID-19 and its variants: What's the latest?

Which vaccine for which age group? 

The coronavirus vaccination campaign has started, with 3 available vaccines, developed by the Pfizer-BioNTech®, Oxford University-AstraZeneca® and Moderna® labs. A number of other vaccines are currently being trialled and/or are awaiting approval in the UK, including the Valneva®, Novavax®, and Johnson & Johnson® vaccines.

Guidance has been put in place to allow as many people as possible to be vaccinated, in order of the priority groups listed in the following image:

Source: BBC

After concerns early in the year within the EU about potential risk of blood clots in younger recipients of the AstraZeneca® vaccine, the European Medicines Agency (EMA) temporarily suspended its use. After thorough examination, both the EMA and the UK Medicines & Healthcare products Regulatory Agency concluded that the vaccine was both effective and safe for use. While some EU countries have reserved the AstraZeneca® for older recipients, this is not being done in the UK and the vaccine is available to all age groups.

As of 30 March, 2021 COVID-19 vaccines are available in the UK for the following groups:

• People aged 50+
• People at high risk from coronavirus (clinically extremely vulnerable)
• People who live or work in care homes
• Health and social care workers
• People with a condition that puts them at higher risk (clinically vulnerable, see list below)
• People with a learning disability
• People who are a primary carer for someone who is at high risk

Conditions that are considered to put a person at higher risk include:

• Long-term lung conditions (i.e. severe asthma, COPD, cystic fibrosis, bronchiectasis)
• Long-term cardiovascular conditions (i.e. congenital heart disease, heart failure, peripheral arterial disease)
• Diabetes
• Chronic kidney disease (CKD)
• Long-term liver conditions (i.e. cirrhosis, hepatitis)
• Conditions affecting the brain or nerves (i.e. dementia, Alzheimer's, Parkinson's, multiple sclerosis, cerebral palsy, epilepsy, stroke, motor neurone disease)
• Conditions or treatments that put you at higher risk of infection (i.e. HIV or certain treatments for lupus, psoriasis or rheumatoid arthritis)
• Learning disabilities
• Severe mental conditions (i.e. bipolar disorder, schizophrenia)
• Severe obesity (a BMI of 40+)

Vaccination and specific cases

• Pregnant women: There is no known risk with giving inactivated virus or bacterial vaccines during pregnancy. However, there is still little data on the COVID vaccine in pregnant women, so it is recommended to consult a health care professional (doctor, midwife or gynaecologist) to assess the situation and the benefit/risk of vaccination on a case by case basis. 
• People who have already had COVID-19: When infected by the coronavirus, patients develop a lasting immunity. However, it is still unclear how long that immunity lasts. Therefore, people who have already had COVID-19 should get vaccinated. There is no evidence of any safety concerns from vaccinating people who have had COVID in the past or who currently have the COVID-19 antibodies.
  But, you can have the vaccine 28 days after your first positive COVID-19 test or 28 days after symptoms first appears, so you may need to wait.
• People who have been in contact with someone who has COVID-19: People who have been in contact with someone who has tested positive for COVID-19 should wait for a negative COVID test result before receiving the jab.

Vaccines and the COVID-19 variants

The SARS-CoV-2 epidemic has been a global phenomenon for more than a year. The appearance of variants makes the fight against the virus even more complex. Indeed, it is important to detect these variants and to study them in order to be able to anticipate the potential consequences that they may have on the population.

A variant is an organism that differs from the original virus (in this case SARS-CoV-2) by several mutations. A mutation is the substitution of one RNA base (in the case of RNA viruses) by another during a replication error, which results in the modification of the corresponding amino acid on the protein coded by the mutated gene. This mutation can result in a substitution (one amino acid replaces another), a deletion (one amino acid is lost), an insertion (a new amino acid is introduced into the protein), a duplication (one amino acid is abnormally repeated), etc.

Not all variants of the COVID-19 virus are more virulent or more infectious than the original virus. The ones we will be looking out for in particular are the so-called "variants of concern" (VOC). These are either more contagious, more virulent or are capable of immune evasion (an ability to evade a host's immune response to either spread to a new host or to continue growing). 

The three variants that we have been hearing a lot about are the following: 

Source: European Centre for Disease Prevention and Control

• Lineage B.1.1.7, also known as VOC-20DEC-01 or the UK variant: This variant was first detected in and spread from South East England (Kent) and is defined by 23 mutations from the original coronavirus. This variant is 50-70% more transmissible than the original Sars-CoV-2, but is no more or less virulent. The main concern for this variant surrounds its mutations that impact the structure of the Spike protein, which allows the virus to enter and infect our cells. The Spike protein is also the target of the current vaccines on the market.
  Additionally, this variant was initially not detected by certain PCR tests, resulting in false negatives. Since then, all commercial tests now detect the UK variant.
• Lineage B.1.351, also known as 501 Y.V2 or the South African variant: This variant, first detected in the Eastern Cape province of South Africa, also has mutations in its Spike protein and is more transmissible than the original COVID variant. Cases of re-infection have also been seen with this variant. Initial data has shown that the AstraZeneca® vaccine does not appear to be sufficiently effective against this variant, but the Pfizer-BioNTech® and Moderna® messenger RNA vaccines have shown efficacy against it. 
• Lineage P.1, also known as VOC-202101/02 or the Brazil(ian) variant: The mutations in this strain seem to give it increased transmissibility as well as increased resistance to immunity. 

Both the South African and Brazilian variants have been found in the UK, but are less common than the UK variant.

A French variant was also discovered on 15 March 2021 in Brittany. There is little information to date about the transmissibility and virulence of this variant. However, it seems that this strain is less detectable by PCR tests. Studies on the latter are underway. 

The emergence of these variants is prompting pharmaceutical companies to continue research into existing and future vaccines.  

Have you been vaccinated against the coronavirus? What do you think of the available vaccines? 

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