The world’s first human challenge trial for a vaccine against SARS-CoV-2 is set to begin in London in January. Human challenge trials for the SARS-CoV-2 virus have many challenges, including producing a strain that is less virulent, but Dr. Gagandeep Kang says such trials can provide information and help design better vaccines than we can do now with conventional trials.
While in-flight transmission of novel coronavirus among passengers is considered to be low, three studies have found instances where coronavirus transmission had probably taken place in-flight. The spread has probably become possible as mask wearing was not compulsory early in the pandemic. But thermal imaging, which has been in place since the beginning, has been found wanting.
Based on experiments and simulations, researchers have found that air emitted during plosive speech sounds — where a consonant (P, B, T, D, K and G) is produced by stopping the airflow using the lips, tongue tip or body followed by a sudden release of air — lead to significantly enhanced directed transport of the virus. When the speech contains a train of such puffs a continuous, turbulent, jet-like flow is formed and is capable of transporting air and droplets to over two metres in just 30 seconds.
Of the 1,140 pregnant women presenting at 15 hospitals in Maharashtra, 141 were found to be infected with novel coronavirus, translating to 12.3% prevalence. Pooled data of 141 pregnant women and 180 women from Nair Hospital in Mumbai revealed that only 11.5% of those infected showed symptoms, while the remaining 88.5% were asymptomatic.
A draft of the proposed changes to its recommendations, which was later withdrawn pending finalisation, the CDC confirmed that airborne particles can spread even by breathing, remain suspended in air and be inhaled and spread beyond six feet in certain enclosed settings.
On September 21, CDC removed the revised coronavirus spread guidance that acknowledged airborne transmission through aerosols, saying it was “posted in error”. The revised guidance posted three days ago stated that particles carrying the virus can remain suspended in air and spread to distances beyond six feet and is the “main way” the virus spreads.
On September 18, CDC revised its guidelines to acknowledge that the “main way” the novel coronavirus (SARS-CoV-2) spreads is through aerosols. It also for the first time mentions that virus can spread through breathing, stay suspended in air and travel to distances beyond six feet.
A study that monitored 10 healthy individuals for more than 35 years revealed that reinfection with the same seasonal coronavirus occurred frequently at 12 months after infection. This suggests that the duration of protection against SARS-CoV-2 reinfection too may not be long.