J&J JNJ announced data from a phase III study and the real world, which showed that a booster shot of its adenovirus-based, single-shot vaccine increases protection against the infection.Additional data from the phase III ENSEMBLE study showed that a booster dose given 56 days after the first jab led to 94% protection against symptomatic (moderate to severe/critical) COVID-19 in the United States and 75% protection globally. Meanwhile, the “second” or booster shot provided 100% protection against severe/critical COVID-19 — at least 14 days post-final vaccination.The data demonstrated that when the booster jab was given two months after the first shot, antibody levels were four to six times higher than observed after the first vaccination. Also, antibody levels increased nine-fold one week after the booster dose when the same was given six months after the first shot,J&J also said that the phase III data together with real-world evidence confirmed its vaccine’s strong and long-lasting protection against COVID-19-related hospitalizations and death even after a single shot.Last month, J&J released data from two phase I/IIa studies on its vaccine’s booster shot. The data showed that its COVID-19 vaccine booster, after the single dose primary regimen, led to a rapid and robust increase in spike-binding antibodies. These antibody levels were nine-fold higher than 28 days after the primary single-dose vaccination.J&J has submitted the latest additional data to the FDA and plans to submit the same to other regulators like the World Health Organization (WHO) soon.This year so far, J&J’s shares have risen 4.5% compared with an increase of 8.4% for the industry.Image Source: Zacks Investment ResearchOther COVID vaccine makers, Pfizer PFE/BioNTech BNTX and Moderna MRNA have already submitted an application for authorization/approval for a booster dose of its COVID-19 vaccine and have provided clinical data to support the efficacy of a booster dose to the FDA.The United States is recording around 130,000-new cases per day as the pace of infection has gained traction since July mainly due to the spread of the Delta variant. A booster dose, given 6-12 months after the primary two-dose schedule, can help enhance immunity, and thus sustain protection from COVID-19.Booster doses have demonstrated a manifold increase in the immunity levels compared to the levels achieved following the initial regimen in clinical studies. Data from some studies have suggested declining efficacy of COVID-19 vaccines over time against symptomatic infection or the Delta variant.Though none of the marketed COVID-19 vaccines are yet approved as a booster dose, last month, the FDA expanded the EUA of Pfizer and Moderna’s vaccines to allow the third dose to be administered to certain immunocompromised individuals like those who have undergone solid organ transplantation or have been diagnosed with other diseases that may have weakened their immune systems. However, an amendment to the EUA to include immunocompromised individuals in the authorized label of J&J’s single-shot, adenovirus-based COVID-19 vaccine was not enacted due to insufficient data.Earlier this week, an FDA advisory committee voted against approval of the booster or “third” dose of Pfizer/BioNTech’s mRNA-based COVID-19 vaccine, Comirnaty, for the entire population for which Pfizer and BioNTech were seeking approval (people 16 years of age and older). The committee, however, recommended approving the dose for people aged 65 years or older. The FDA’s decision on Pfizer/BioNTech’s booster shots is expected in the next few weeks.J&J currently carries a Zacks Rank #2 (Buy). You can see the complete list of today’s Zacks #1 Rank (Strong Buy) stocks here. Infrastructure Stock Boom to Sweep America A massive push to rebuild the crumbling U.S. infrastructure will soon be underway. It’s bipartisan, urgent, and inevitable. Trillions will be spent. Fortunes will be made. The only question is “Will you get into the right stocks early when their growth potential is greatest?” Zacks has released a Special Report to help you do just that, and today it’s free. Discover 7 special companies that look to gain the most from construction and repair to roads, bridges, and buildings, plus cargo hauling and energy transformation on an almost unimaginable scale.Download FREE: How to Profit from Trillions on Spending for Infrastructure >>Want the latest recommendations from Zacks Investment Research? Today, you can download 7 Best Stocks for the Next 30 Days. Click to get this free report Johnson & Johnson (JNJ): Free Stock Analysis Report Pfizer Inc. (PFE): Free Stock Analysis Report Moderna, Inc. (MRNA): Free Stock Analysis Report BioNTech SE Sponsored ADR (BNTX): Free Stock Analysis Report To read this article on Zacks.com click here. Zacks Investment Research