* Brazil stocks at highest level since March 5 * Peru"s sol hits low of 3.6678 on fears of political vacuum * Stronger oil prices boost Mexican, Colombian pesos (Updates comments, prices) By Shriya Ramakrishnan and Ambar Warrick Nov 16 (Reuters) - Most Latin American currencies trimmed initial gains on Monday on news of another promising COVID-19 vaccine, while political uncertainty pushed Peru"s sol to a record low after the country"s interim leader resigned. Drugmaker Moderna Inc said its experimental vaccine was 94.5% effective in preventing COVID-19 based on interim data from a late-stage clinical trial, making it the second U.S. drugmaker to report better-than-expected results. The announcement sparked a global market rally on hopes for a swifter economic recovery from the pandemic. But as with last week, when Pfizer Inc reported positive vaccine trial data, regional currencies sharply pared initial gains. Most Latam currencies had ended last week lower despite an initial boost from the vaccine news and the U.S. elections. Brazil"s real traded 0.7% higher after rising as much as 1.7%, while Sao Paulo stocks jumped as much as 1.5% to a more than eight-month high. Sentiment for Brazil was further boosted by a central bank survey showing an improved 2020 growth outlook for Latin America"s largest economy. "If last week was any guide, the positive sentiment might be short-lived. While unambiguously good news, we think markets are overestimating the timing and scalability of vaccine implementation," Mazen Issa, senior FX strategist at TD Securities, cautioned in a note. Peru"s sol weakened 0.6% and the country"s sovereign dollar bonds turned lower, after lawmakers failed to name a successor to departed interim president Manuel Merino. The political upheaval adds to uncertainty facing Peru, the world"s no. 2 copper producer, as it battles the coronavirus pandemic and possibly its worst economic contraction in a century. "The impeachment and resignation of two presidents in one week is clearly a risk-off event, and with popular sentiment firmly in opposition to the former, this is a recipe for further political unrest," said Ilya Gofshteyn, senior emerging markets macro strategist at Standard Chartered. Mexico"s peso and Colombia"s peso rose on strength in oil prices, as news of the vaccine boosted demand prospects. Local markets in Mexico and Colombia were shut for a holiday. A gauge of Latin American stocks gained about 1.9%, while stocks in Chile climbed to a more than three-month high. But Chile"s peso traded flat, weighed down by threats of strikes at some of its copper mines. Key Latin American stock indexes and currencies: Latest Daily % change MSCI Emerging Markets 1203.13 1.24 MSCI LatAm 2122.39 1.97 Brazil Bovespa 105844.35 1.07 Chile IPSA 4046.30 1.02 Argentina MerVal 50813.73 1.84 Currencies Latest Daily % change Brazil real 5.4355 0.71 Mexico peso 20.3373 0.27 Chile peso 766.5 -0.01 Colombia peso 3627.45 0.37 Peru sol 3.6627 -0.60 Argentina peso 79.9500 -0.25 (interbank) (Reporting by Shriya Ramakrishnan in Bengaluru; Editing by Edmund Blair, Bernadette Baum and Richard Chang)