A new nasally administered Covid-19 vaccine has shown promise in protecting patients from both Omicron infection and disease progression, according to a recent study published in The Lancet. This vaccine, known as Ad5-nCoV, is the world's first licensed nasal vaccine and has been found to be more effective against the Omicron variant compared to traditional vaccines used throughout the pandemic.
The study, conducted by Li et al., involved over 10,000 patients who received the nasal vaccine as a booster dose. The researchers found that four weeks after receiving the nasal vaccine, 65% of participants in the immunogenicity subgroup had detectable neutralizing antibodies against the BA.4/5 variants of Omicron. In comparison, only 2% of those who received a control vaccine had these antibodies. Additionally, the average antibody titer count in the nasal vaccine group was over six times higher than the control group.
While the nasal vaccine showed a higher antibody response, it did not completely prevent infections. Only 35.1% of participants were protected from infection at their 12-month follow-up. However, the primary goal of Covid-19 vaccines is to prevent progression to severe disease, and in this regard, the nasal vaccine was successful. It kept infected patients to only mild symptoms 98.1% of the time.
The study also found that T cell responses in the nasal vaccine group were significantly higher than in the control group, indicating a stronger adaptive immune response to clear the virus post-infection.
Although the nasal vaccine did show an increase in adverse reactions compared to the control group, the majority of these reactions were relatively mild, such as coughing or sneezing. The benefits of the nasal vaccine, including a significant increase in antibody responses, outweighed these drawbacks.
In conclusion, the Ad5-nCoV nasal vaccine offers a promising alternative to intramuscular vaccination. It has shown greater effectiveness against Omicron and its variants, with higher antibody and T cell responses. If this vaccine becomes available to the public, it could be a valuable tool in combating the ongoing evolution of SARS-CoV-2. It is recommended that individuals receive additional doses of Covid-19 vaccine every three to six months to maintain antibody levels, and the nasal vaccine could be a valuable addition to the vaccine options available.