The news earlier this week that China and India plan to roll out nasal vaccines underscores the fact that better protection is still needed against getting and transmitting COVID-19 in the first place. 

In the U.S., the currently available shots do a good job at protecting people from ending up in the hospital or dying. The new generation of COVID-19 vaccines are expected to be even better. But the difference between what a nasal vaccine and an intramuscular vaccine can do is remarkably different, primarily by providing mucosal immunity, which we don’t get from shots in arms.

“The nasal vaccine is the best way to stop transmission or block it to the hilt,” Dr. Eric Topol, director of the Scripps Research Translational Institute, told MarketWatch earlier this summer. “Because it basically prevents the virus from getting into the nasal mucosa, and it produces the IgA antibodies that you don’t get now with the shots.”

The CanSino Biologics 688185, +0.29% inhaled vaccine in China and the Bharat Biotech nasal vaccine in India are just two of the at least 100 oral or nasal vaccines in development around the world, according to Nature. In the U.S., there is work underway to develop a nasal vaccine at Mt. Sinai, CyanVac, and Xanadu Bio. (Both companies are privately held.)

Even the World Health Organization weighed in on nasal vaccines this week.

“The advantage that nasal vaccines bring is that you’re generating the immune response on the surfaces of the respiratory mucosa in the lungs,” said Dr. Michael Ryan, a WHO health official. “In effect, you’re generating the first line of defense at where the virus enters and causes a lot of damage.”

Other COVID-19 news to know: 

Moderna MRNA, +0.71% predicts the market for annual COVID-19 shots in the U.S. could be as high as $12.9 billion—or as low as $5.2 billion, according to Bloomberg. Earlier this week, health officials said they expect a COVID-19 booster to be needed every fall, much like a flu shot. 

Vitamin D supplements don’t prevent COVID-19 infections or getting sick with other respiratory diseases, according to a new randomized, controlled clinical trial in the U.K. Another study that gave cod liver oil, which is considered a low-dose vitamin D supplement, to Norwegians had a similar finding. Both studies were published this month in the British Medical Journal. “The major takeaway is that for people in general a vitamin D supplement did not prevent COVID-19, serious COVID-19, or symptomatic acute respiratory tract infections,” Dr. Arne Søraas, a researcher at Oslo University Hospital, told CNN. 

The seven-day average for new COVID-19 cases continued its two-month downtrend, as it fell below the 70,000 mark for the first time in four months. The daily average was 68,356 on Thursday, down 25% from two weeks ago, according to a New York Times tracker. The daily average for hospitalizations fell to 35,388, while the daily average for deaths fell to a two-month low of 383 on Thursday. – Tomi Kilgore