Russian coronavirus vaccine shows no serious side-effects, triggers antibody response in early trials

As people across the globe wait for a safe, effective coronavirus vaccine to emerge, Russian scientists reveal their version may be ready for distribution sooner than later.

MOSCOW, Russia — While “Operation Warp Speed” is helping the United States sprint towards a coronavirus vaccine, other countries are also making progress in stopping the global pandemic. Russian scientists reveal their potential COVID vaccine is successfully battling the virus while only causing mild side-effects.

Their report in The Lancet shows a two-part vaccine may be the key to keeping patients from becoming resistant to the drug.

In two recent trials, a total of 76 people took part in the 42-day tests which experiments with both a frozen and freeze-dried formula. Researchers say the frozen version of the vaccine would likely be shipped around the globe like normal medications. Their freeze-dried formula is said to be more stable and ideal for use in hard-to-reach regions if kept in cold storage (2-8 degrees Celsius).

During the phase 1 trial, scientists only gave participants one portion of the coronavirus vaccine. This tests how the human body reacts to the medication and what side-effects emerge. The results find the most common adverse effects include pain at injection site (58% of the 76 patients), running a high temperature (50%), headache (42%), lack of energy (28%), and muscle or joint pain (24%). Fortunately, the effects seem to be minor and researchers note these symptoms are typical after taking other vaccines as well.

In phase 2, the study reports all patients receiving both parts of the vaccine are now producing antibodies against SARS-CoV-2, the virus causing COVID-19. More importantly, all patients in the phase 2 are producing neutralizing antibodies by Day 42. This is important as neutralizing antibodies help the body protect against re-infection from illnesses.

Two vectors better than one

The Russian formula uses two adenovirus vectors, recombinant human adenovirus type 26 (rAd26-S) and recombinant human adenovirus type 5 (rAd5-S). Adenoviruses are weak strains of the common cold which don’t replicate and don’t get people sick. Scientists use them to deliver genetic material into patients which codes itself to seek out the “spike” protein of SARS-CoV-2.

Coded cells head to the lymph nodes where the immune system creates new antibodies that recognize coronavirus and attack it. The spike protein of SARS-CoV-2 is the virus’s defining feature. It grabs on to specific genes (ACE-2) on the surface of human cells and then slices into them; hijacking cells and making them reproduce the virus.

Using two different adenovirus vectors, researchers hope to keep humans from developing a tolerance to their vaccine. They add that the body can start creating antibodies to adenoviruses as well as COVID-19.

“To form a powerful immune response against SARS-CoV-2, it is important that a booster vaccination is provided. However, booster vaccinations that use the same adenovirus vector might not produce an effective response, because the immune system may recognize and attack the vector,” explains Dr. Denis Logunov in a media release.

“This would block the vaccine from entering people’s cells and teaching the body to recognize and attack SARS-CoV-2. For our vaccine, we use two different adenovirus vectors in a bid to avoid the immune system becoming immune to the vector.”

Phase 2 gives patients the rAd26-S dose on the first day of testing, followed by rAd5-S on day 21. The report also shows a two-dose may be necessary. Only 61 percent of the people in phase 1 (which only gives one dose) develop neutralizing antibodies to COVID-19.

Helping the healing process

The results compare the potential vaccine to the blood of nearly 5,000 recovering COVID-19 patients. The Russian team says people receiving the vaccine have a higher antibody response than those recovering from COVID without it. Both groups have about the same level of neutralizing antibodies in their systems.

Researchers add that even when some patients develop neutralizing antibodies to one of the adenovirus vectors, they do not impact the other part of the vaccine. Patients continue to fight coronavirus regardless of the body targeting one of these vectors.

T cell response, the body’s ability to fight off infections, also sees a boost. All patients in phase 2 saw a T cell response within 28 days. This includes both T-helper (CD4) cells and T-killer (CD8) cells forming in vaccinated individuals.

The frozen formula tends to have slightly better results, causing T-helpers to increase by 2.5 percent and T-killers to rise by 1.3 percent. The freeze-dried vaccine only produces a 1.3 percent and 1.1 percent increase, respectively.

Coronavirus vaccine a work in progress

Study authors caution these trials aren’t at the finish line yet. Although the study group includes people between 18 and 60 years-old, most participants are in their 20’s and 30’s. Phase 3 trials will focus on a much larger group and also study the vaccine’s effects on older patients.

“The phase 3 clinical trial of our vaccine was approved on 26 August 2020. It is planned to include 40,000 volunteers from different age and risk groups, and will be undertaken with constant monitoring of volunteers through an online application,” says Professor Alexander Gintsburg.

“In view of the ongoing painful toll of the COVID-19 pandemic and its magnitude, the more vaccine candidates that have successful early results the better. Ultimately, all vaccine candidates will need to show safety and prove durable clinical efficacy (including in groups at greater risk) in large randomized trials before they can be put into widespread use.”

The study appears in the Sept. 4 edition of The Lancet.

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